diff --git a/gems/aws-sdk-s3/CHANGELOG.md b/gems/aws-sdk-s3/CHANGELOG.md
index 7fd43ebaea8..9b595d882c0 100644
--- a/gems/aws-sdk-s3/CHANGELOG.md
+++ b/gems/aws-sdk-s3/CHANGELOG.md
@@ -1,6 +1,8 @@
 Unreleased Changes
 ------------------
 
+* Feature - TODO
+
 1.199.1 (2025-09-25)
 ------------------
 
diff --git a/gems/aws-sdk-s3/lib/aws-sdk-s3/customizations.rb b/gems/aws-sdk-s3/lib/aws-sdk-s3/customizations.rb
index c0dba64b79c..a85bfd6e14c 100644
--- a/gems/aws-sdk-s3/lib/aws-sdk-s3/customizations.rb
+++ b/gems/aws-sdk-s3/lib/aws-sdk-s3/customizations.rb
@@ -6,6 +6,7 @@ module S3
     autoload :BucketRegionCache, 'aws-sdk-s3/bucket_region_cache'
     autoload :Encryption, 'aws-sdk-s3/encryption'
     autoload :EncryptionV2, 'aws-sdk-s3/encryption_v2'
+    autoload :DefaultExecutor, 'aws-sdk-s3/default_executor'
     autoload :FilePart, 'aws-sdk-s3/file_part'
     autoload :FileUploader, 'aws-sdk-s3/file_uploader'
     autoload :FileDownloader, 'aws-sdk-s3/file_downloader'
@@ -18,6 +19,8 @@ module S3
     autoload :ObjectMultipartCopier, 'aws-sdk-s3/object_multipart_copier'
     autoload :PresignedPost, 'aws-sdk-s3/presigned_post'
     autoload :Presigner, 'aws-sdk-s3/presigner'
+    autoload :DirectoryUploader, 'aws-sdk-s3/directory_uploader'
+    autoload :DirectoryDownloader, 'aws-sdk-s3/directory_downloader'
     autoload :TransferManager, 'aws-sdk-s3/transfer_manager'
 
     # s3 express session auth
diff --git a/gems/aws-sdk-s3/lib/aws-sdk-s3/customizations/object.rb b/gems/aws-sdk-s3/lib/aws-sdk-s3/customizations/object.rb
index 0a9a9b9d3ca..69e7d6905b9 100644
--- a/gems/aws-sdk-s3/lib/aws-sdk-s3/customizations/object.rb
+++ b/gems/aws-sdk-s3/lib/aws-sdk-s3/customizations/object.rb
@@ -459,11 +459,17 @@ def upload_stream(options = {}, &block)
       # @see Client#upload_part
       def upload_file(source, options = {})
         uploading_options = options.dup
-        uploader = FileUploader.new(multipart_threshold: uploading_options.delete(:multipart_threshold), client: client)
+        executor = DefaultExecutor.new(max_threads: uploading_options.delete(:thread_count))
+        uploader = FileUploader.new(
+          client: client,
+          executor: executor,
+          multipart_threshold: uploading_options.delete(:multipart_threshold)
+        )
         response = Aws::Plugins::UserAgent.metric('RESOURCE_MODEL') do
           uploader.upload(source, uploading_options.merge(bucket: bucket_name, key: key))
         end
         yield response if block_given?
+        executor.shutdown
         true
       end
       deprecated(:upload_file, use: 'Aws::S3::TransferManager#upload_file', version: 'next major version')
@@ -539,10 +545,12 @@ def upload_file(source, options = {})
       # @see Client#get_object
       # @see Client#head_object
       def download_file(destination, options = {})
-        downloader = FileDownloader.new(client: client)
+        executor = DefaultExecutor.new(max_threads: options[:thread_count])
+        downloader = FileDownloader.new(client: client, executor: executor)
         Aws::Plugins::UserAgent.metric('RESOURCE_MODEL') do
           downloader.download(destination, options.merge(bucket: bucket_name, key: key))
         end
+        executor.shutdown
         true
       end
       deprecated(:download_file, use: 'Aws::S3::TransferManager#download_file', version: 'next major version')
diff --git a/gems/aws-sdk-s3/lib/aws-sdk-s3/default_executor.rb b/gems/aws-sdk-s3/lib/aws-sdk-s3/default_executor.rb
new file mode 100644
index 00000000000..38158b343d7
--- /dev/null
+++ b/gems/aws-sdk-s3/lib/aws-sdk-s3/default_executor.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+module Aws
+  module S3
+    # @api private
+    class DefaultExecutor
+      RUNNING = :running
+      SHUTTING_DOWN = :shutting_down
+      SHUTDOWN = :shutdown
+
+      def initialize(options = {})
+        @max_threads = options[:max_threads] || 10
+        @state = RUNNING
+        @queue = Queue.new
+        @pool = []
+        @mutex = Mutex.new
+      end
+
+      def post(*args, &block)
+        raise 'Executor is not accepting new tasks' unless @state == RUNNING
+
+        @queue << [args, block]
+        ensure_worker_available
+      end
+
+      def kill
+        @mutex.synchronize do
+          @state = SHUTDOWN
+          @pool.each(&:kill)
+          @pool.clear
+          @queue.clear
+        end
+        true
+      end
+
+      def shutdown(timeout = nil)
+        @mutex.synchronize do
+          return true if @state == SHUTDOWN
+
+          @state = SHUTTING_DOWN
+        end
+
+        @max_threads.times { @queue << :shutdown }
+
+        if timeout
+          @pool.each { |thread| thread.join(timeout) }
+          @pool.select(&:alive?).each(&:kill)
+        else
+          @pool.each(&:join)
+        end
+
+        @pool.clear
+        @state = SHUTDOWN
+        true
+      end
+
+      def running?
+        @state == RUNNING
+      end
+
+      def shutting_down?
+        @state == SHUTTING_DOWN
+      end
+
+      def shutdown?
+        @state == SHUTDOWN
+      end
+
+      private
+
+      def ensure_worker_available
+        @mutex.synchronize do
+          return unless @state == RUNNING
+
+          @pool.select!(&:alive?)
+          @pool << spawn_worker if @pool.size < @max_threads
+        end
+      end
+
+      def spawn_worker
+        Thread.new do
+          while (job = @queue.shift)
+            break if job == :shutdown
+
+            args, block = job
+            block.call(*args)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/gems/aws-sdk-s3/lib/aws-sdk-s3/directory_downloader.rb b/gems/aws-sdk-s3/lib/aws-sdk-s3/directory_downloader.rb
new file mode 100644
index 00000000000..86d849f72fd
--- /dev/null
+++ b/gems/aws-sdk-s3/lib/aws-sdk-s3/directory_downloader.rb
@@ -0,0 +1,155 @@
+# frozen_string_literal: true
+
+module Aws
+  module S3
+    # Raised when DirectoryDownloader fails to download objects from S3 bucket
+    class DirectoryDownloadError < StandardError
+      def initialize(message, errors = [])
+        @errors = errors
+        super(message)
+      end
+
+      # @return [Array<StandardError>] The list of errors encountered when downloading objects
+      attr_reader :errors
+    end
+
+    # @api private
+    class DirectoryDownloader
+      def initialize(options = {})
+        @client = options[:client] || Client.new
+        @executor = options[:executor] || DefaultExecutor.new
+        @options = options
+        @abort_download = false
+      end
+
+      attr_reader :client, :abort_download
+
+      # TODO: need to add progress tracker
+      def download(destination, bucket:, **options)
+        if File.exist?(destination)
+          raise ArgumentError 'invalid destination, expected a directory' unless File.directory?(destination)
+        else
+          FileUtils.mkdir_p(destination)
+        end
+
+        download_opts = options.dup
+        @bucket = bucket
+        @ignore_failure = download_opts.delete(:ignore_failure) || false
+        @errors = []
+
+        downloader = FileDownloader.new(client: client, executor: @executor)
+        producer = ObjectProducer.new(destination, build_producer_opts(download_opts))
+        producer.run
+
+        downloads = process_download_queue(producer, downloader, download_opts)
+        build_result(downloads)
+      ensure
+        @executor.shutdown unless @options[:executor]
+      end
+
+      def build_producer_opts(opts)
+        {
+          directory_downloader: self,
+          client: @client,
+          bucket: @bucket,
+          s3_prefix: opts.delete(:s3_prefix),
+          ignore_failure: @ignore_failure,
+          filter_callback: opts.delete(:filter_callback),
+          errors: @errors
+        }
+      end
+
+      def build_result(download_count)
+        downloads = [download_count - @errors.count, 0].max
+
+        if @abort_download
+          msg = "failed to download directory: downloaded #{downloads} files " \
+            "and failed to download #{@errors.count} files."
+          raise DirectoryDownloadError.new(msg, @errors)
+        else
+          result = { completed_downloads: downloads, failed_downloads: @errors.count }
+          result[:errors] = @errors if @errors.any?
+          result
+        end
+      end
+
+      def process_download_queue(producer, downloader, opts)
+        download_attempts = 0
+        completion_queue = Queue.new
+        queue_executor = DefaultExecutor.new
+        while (object = producer.object_queue.shift) != :done
+          break if @abort_download
+
+          download_attempts += 1
+          queue_executor.post(object) do |o|
+            dir_path = File.dirname(o[:path])
+            FileUtils.mkdir_p(dir_path) unless dir_path == @destination || Dir.exist?(dir_path)
+
+            downloader.download(o[:path], opts.merge(bucket: @bucket, key: o[:key]))
+          rescue StandardError => e
+            @errors << e
+            @abort_download = true unless @ignore_failure
+          ensure
+            completion_queue << :done
+          end
+        end
+        download_attempts.times { completion_queue.pop }
+        download_attempts
+      ensure
+        queue_executor.shutdown
+      end
+
+      # @api private
+      class ObjectProducer
+        def initialize(destination_dir, options = {})
+          @destination_dir = destination_dir
+          @client = options[:client]
+          @bucket = options[:bucket]
+          @s3_prefix = options[:s3_prefix]
+          @ignore_failure = options[:ignore_failure]
+          @filter_callback = options[:filter_callback]
+          @errors = options[:errors]
+          @directory_downloader = options[:directory_downloader]
+          @object_queue = SizedQueue.new(100)
+        end
+
+        attr_reader :object_queue
+
+        def run
+          Thread.new do
+            stream_objects
+            @object_queue << :done
+          end
+        end
+
+        private
+
+        def build_object_entry(key)
+          { path: File.join(@destination_dir, normalize_key(key)), key: key }
+        end
+
+        # TODO: need to add filter callback, double check handling of objects that ends with /
+        def stream_objects(continuation_token: nil)
+          resp = @client.list_objects_v2(bucket: @bucket, continuation_token: continuation_token)
+          resp.contents.each do |o|
+            break if @directory_downloader.abort_download
+            next if o.key.end_with?('/')
+
+            @object_queue << build_object_entry(o.key)
+          rescue StandardError => e
+            @errors << e
+            @abort_download = true unless @ignore_failure
+          end
+          stream_objects(continuation_token: resp.next_continuation_token) if resp.next_continuation_token
+        end
+
+        def normalize_key(key)
+          key = key.delete_prefix(@s3_prefix) if @s3_prefix
+          return key if File::SEPARATOR == '/'
+
+          key.tr('/', File::SEPARATOR)
+        end
+      end
+    end
+  end
+end
diff --git a/gems/aws-sdk-s3/lib/aws-sdk-s3/directory_uploader.rb b/gems/aws-sdk-s3/lib/aws-sdk-s3/directory_uploader.rb
new file mode 100644
index 00000000000..d7d87a58311
--- /dev/null
+++ b/gems/aws-sdk-s3/lib/aws-sdk-s3/directory_uploader.rb
@@ -0,0 +1,215 @@
+# frozen_string_literal: true
+
+require 'set'
+
+module Aws
+  module S3
+    # Raised when DirectoryUploader fails to upload files to S3 bucket
+    class DirectoryUploadError < StandardError
+      def initialize(message, errors = [])
+        @errors = errors
+        super(message)
+      end
+
+      # @return [Array<StandardError>] The list of errors encountered when uploading files
+      attr_reader :errors
+    end
+
+    # @api private
+    class DirectoryUploader
+      def initialize(options = {})
+        @client = options[:client] || Client.new
+        @executor = options[:executor] || DefaultExecutor.new
+        @options = options
+        @abort_upload = false
+      end
+
+      # @return [Client]
+      attr_reader :client
+
+      # @return [Boolean]
+      attr_accessor :abort_upload
+
+      # TODO: Need to add progress tracker
+      def upload(source, bucket:, **options)
+        raise ArgumentError, 'Invalid directory' unless Dir.exist?(source)
+
+        upload_opts = options.dup
+        @ignore_failure = upload_opts.delete(:ignore_failure) || false
+        @errors = []
+
+        uploader = FileUploader.new(
+          multipart_threshold: upload_opts.delete(:multipart_threshold),
+          client: @client,
+          executor: @executor
+        )
+        producer = FileProducer.new(source, build_producer_opts(upload_opts))
+        producer.run
+        uploads = process_upload_queue(producer, uploader, upload_opts.merge(bucket: bucket))
+        build_result(uploads)
+      ensure
+        @executor.shutdown unless @options[:executor]
+      end
+
+      private
+
+      def build_producer_opts(opts)
+        {
+          directory_uploader: self,
+          s3_prefix: opts.delete(:s3_prefix),
+          recursive: opts.delete(:recursive),
+          follow_symlinks: opts.delete(:follow_symlinks),
+          filter_callback: opts.delete(:filter_callback),
+          ignore_failure: @ignore_failure,
+          errors: @errors
+        }
+      end
+
+      def build_result(upload_count)
+        uploads = [upload_count - @errors.count, 0].max
+
+        if @abort_upload
+          msg = "failed to upload directory: uploaded #{uploads} files " \
+            "and failed to upload #{@errors.count} files."
+          raise DirectoryUploadError.new(msg, @errors)
+        else
+          result = { completed_uploads: uploads, failed_uploads: @errors.count }
+          result[:errors] = @errors if @errors.any?
+          result
+        end
+      end
+
+      def process_upload_queue(producer, uploader, opts)
+        upload_attempts = 0
+        completion_queue = Queue.new
+        queue_executor = DefaultExecutor.new
+        while (file = producer.file_queue.shift) != :done
+          break if @abort_upload
+
+          upload_attempts += 1
+          queue_executor.post(file) do |f|
+            uploader.upload(f[:path], opts.merge(key: f[:key]))
+          rescue StandardError => e
+            @errors << e
+            @abort_upload = true unless @ignore_failure
+          ensure
+            completion_queue << :done
+          end
+        end
+        upload_attempts.times { completion_queue.pop }
+        upload_attempts
+      ensure
+        queue_executor.shutdown
+      end
+
+
+      # @api private
+      class FileProducer
+        def initialize(source_dir, options = {})
+          @source_dir = source_dir
+          @s3_prefix = options[:s3_prefix]
+          @recursive = options[:recursive] || false
+          @follow_symlinks = options[:follow_symlinks] || false
+          @ignore_failure = options[:ignore_failure]
+          @filter_callback = options[:filter_callback]
+          @errors = options[:errors]
+          @directory_uploader = options[:directory_uploader]
+          @file_queue = SizedQueue.new(100)
+        end
+
+        attr_accessor :file_queue
+
+        def run
+          Thread.new do
+            if @recursive
+              find_recursively
+            else
+              find_directly
+            end
+            @file_queue << :done
+          end
+        end
+
+        private
+
+        def build_file_entry(file_path, key)
+          normalized_key = @s3_prefix ? File.join(@s3_prefix, key) : key
+          { path: file_path, key: normalized_key }
+        end
+
+        def find_directly
+          Dir.each_child(@source_dir) do |entry|
+            break if @directory_uploader.abort_upload
+
+            entry_path = File.join(@source_dir, entry)
+            next if File.directory?(entry_path) || skip_symlink?(entry_path)
+            next unless include_file?(entry_path, entry)
+            next unless valid_file_type?(entry_path)
+
+            @file_queue << build_file_entry(entry_path, entry)
+          rescue StandardError => e
+            @errors << e
+            @directory_uploader.abort_upload = true unless @ignore_failure
+          end
+        end
+
+        def find_recursively
+          if @follow_symlinks
+            visited = Set.new
+            visited << File.stat(@source_dir).ino
+            scan_directory(@source_dir, visited: visited)
+          else
+            scan_directory(@source_dir)
+          end
+        end
+
+        def valid_file_type?(path)
+          File.file?(path) || File.symlink?(path)
+        end
+
+        def skip_symlink?(path)
+          !@follow_symlinks && File.symlink?(path)
+        end
+
+        def include_file?(file_path, file_name)
+          return true unless @filter_callback
+
+          @filter_callback.call(file_path, file_name)
+        end
+
+        def scan_directory(dir_path, key_prefix: '', visited: nil)
+          return if @directory_uploader.abort_upload
+
+          Dir.each_child(dir_path) do |entry|
+            break if @directory_uploader.abort_upload
+
+            full_path = File.join(dir_path, entry)
+            next unless include_file?(full_path, entry)
+            next if !@follow_symlinks && File.symlink?(full_path)
+
+            if File.directory?(full_path)
+              handle_directory(full_path, entry, key_prefix, visited)
+            elsif valid_file_type?(full_path)
+              key = key_prefix.empty? ? entry : File.join(key_prefix, entry)
+              @file_queue << build_file_entry(full_path, key)
+            end
+          rescue StandardError => e
+            @errors << e
+            @directory_uploader.abort_upload = true unless @ignore_failure
+          end
+        end
+
+        def handle_directory(dir_path, dir_name, key_prefix, visited)
+          if @follow_symlinks && visited
+            stat = File.stat(dir_path)
+            return if visited.include?(stat.ino)
+
+            visited << stat.ino
+          end
+          new_prefix = key_prefix.empty? ? dir_name : File.join(key_prefix, dir_name)
+          scan_directory(dir_path, key_prefix: new_prefix, visited: visited)
+        end
+      end
+    end
+  end
+end
diff --git a/gems/aws-sdk-s3/lib/aws-sdk-s3/file_downloader.rb b/gems/aws-sdk-s3/lib/aws-sdk-s3/file_downloader.rb
index 517a06dabea..4181c7eaeac 100644
--- a/gems/aws-sdk-s3/lib/aws-sdk-s3/file_downloader.rb
+++ b/gems/aws-sdk-s3/lib/aws-sdk-s3/file_downloader.rb
@@ -8,184 +8,243 @@ module Aws
   module S3
     # @api private
     class FileDownloader
-
       MIN_CHUNK_SIZE = 5 * 1024 * 1024
       MAX_PARTS = 10_000
+      HEAD_OPTIONS = Set.new(Client.api.operation(:head_object).input.shape.member_names)
+      GET_OPTIONS = Set.new(Client.api.operation(:get_object).input.shape.member_names)
 
       def initialize(options = {})
         @client = options[:client] || Client.new
+        @executor = options[:executor]
       end
 
       # @return [Client]
       attr_reader :client
 
       def download(destination, options = {})
-        valid_types = [String, Pathname, File, Tempfile]
-        unless valid_types.include?(destination.class)
-          raise ArgumentError, "Invalid destination, expected #{valid_types.join(', ')} but got: #{destination.class}"
-        end
-
-        @destination = destination
-        @mode = options.delete(:mode) || 'auto'
-        @thread_count = options.delete(:thread_count) || 10
-        @chunk_size = options.delete(:chunk_size)
-        @on_checksum_validated = options.delete(:on_checksum_validated)
-        @progress_callback = options.delete(:progress_callback)
-        @params = options
-        validate!
+        validate_destination!(destination)
+        opts = build_download_opts(destination, options.dup)
+        validate_opts!(opts)
 
         Aws::Plugins::UserAgent.metric('S3_TRANSFER') do
-          case @mode
-          when 'auto' then multipart_download
-          when 'single_request' then single_request
-          when 'get_range'
-            raise ArgumentError, 'In get_range mode, :chunk_size must be provided' unless @chunk_size
-
-            resp = @client.head_object(@params)
-            multithreaded_get_by_ranges(resp.content_length, resp.etag)
-          else
-            raise ArgumentError, "Invalid mode #{@mode} provided, :mode should be single_request, get_range or auto"
+          case opts[:mode]
+          when 'auto' then multipart_download(opts)
+          when 'single_request' then single_request(opts)
+          when 'get_range' then range_request(opts)
           end
         end
-        File.rename(@temp_path, @destination) if @temp_path
+        File.rename(opts[:temp_path], destination) if opts[:temp_path]
       ensure
-        File.delete(@temp_path) if @temp_path && File.exist?(@temp_path)
+        cleanup_temp_file!(opts)
       end
 
       private
 
-      def validate!
-        return unless @on_checksum_validated && !@on_checksum_validated.respond_to?(:call)
+      def build_download_opts(destination, opts)
+        {
+          destination: destination,
+          mode: opts.delete(:mode) || 'auto',
+          chunk_size: opts.delete(:chunk_size),
+          on_checksum_validated: opts.delete(:on_checksum_validated),
+          progress_callback: opts.delete(:progress_callback),
+          params: opts,
+          temp_path: nil
+        }
+      end
+
+      def cleanup_temp_file!(opts)
+        return unless opts
+
+        temp_file = opts[:temp_path]
+        File.delete(temp_file) if temp_file && File.exist?(temp_file)
+      end
+
+      def download_with_executor(part_list, total_size, opts)
+        download_attempts = 0
+        completion_queue = Queue.new
+        abort_download = false
+        error = nil
+        progress =
+          if (progress_callback = opts[:progress_callback])
+            MultipartProgress.new(part_list, total_size, progress_callback)
+          end
+
+        while (part = part_list.shift)
+          break if abort_download
+
+          download_attempts += 1
+          @executor.post(part) do |p|
+            update_progress(progress, p) if progress
+
+            resp = @client.get_object(p.params)
+            range = extract_range(resp.content_range)
+            validate_range(range, p.params[:range]) if p.params[:range]
+            write(resp.body, range, opts)
+
+            if opts[:on_checksum_validated] && resp.checksum_validated
+              opts[:on_checksum_validated].call(resp.checksum_validated, resp)
+            end
+          rescue StandardError => e
+            abort_download = true
+            error = e
+          ensure
+            completion_queue << :done
+          end
+        end
+
+        download_attempts.times { completion_queue.pop }
+        raise error unless error.nil?
+      end
+
+      def get_opts(opts)
+        GET_OPTIONS.each_with_object({}) { |k, h| h[k] = opts[k] if opts.key?(k) }
+      end
+
+      def head_opts(opts)
+        HEAD_OPTIONS.each_with_object({}) { |k, h| h[k] = opts[k] if opts.key?(k) }
+      end
 
-        raise ArgumentError, ':on_checksum_validated must be callable'
+      def compute_chunk(chunk_size, file_size)
+        raise ArgumentError, ":chunk_size shouldn't exceed total file size." if chunk_size && chunk_size > file_size
+
+        chunk_size || [(file_size.to_f / MAX_PARTS).ceil, MIN_CHUNK_SIZE].max.to_i
       end
 
-      def multipart_download
-        resp = @client.head_object(@params.merge(part_number: 1))
+      def compute_mode(file_size, total_parts, etag, opts)
+        chunk_size = compute_chunk(opts[:chunk_size], file_size)
+        part_size = (file_size.to_f / total_parts).ceil
+
+        resolve_temp_path(opts)
+        if chunk_size < part_size
+          multithreaded_get_by_ranges(file_size, etag, opts)
+        else
+          multithreaded_get_by_parts(total_parts, file_size, etag, opts)
+        end
+      end
+
+      def extract_range(value)
+        value.match(%r{bytes (?<range>\d+-\d+)/\d+})[:range]
+      end
+
+      def multipart_download(opts)
+        resp = @client.head_object(head_opts(opts[:params].merge(part_number: 1)))
         count = resp.parts_count
 
         if count.nil? || count <= 1
           if resp.content_length <= MIN_CHUNK_SIZE
-            single_request
+            single_request(opts)
           else
-            multithreaded_get_by_ranges(resp.content_length, resp.etag)
+            resolve_temp_path(opts)
+            multithreaded_get_by_ranges(resp.content_length, resp.etag, opts)
           end
         else
           # covers cases when given object is not uploaded via UploadPart API
-          resp = @client.head_object(@params) # partNumber is an option
+          resp = @client.head_object(head_opts(opts[:params])) # partNumber is an option
           if resp.content_length <= MIN_CHUNK_SIZE
-            single_request
+            single_request(opts)
           else
-            compute_mode(resp.content_length, count, resp.etag)
+            compute_mode(resp.content_length, count, resp.etag, opts)
           end
         end
       end
 
-      def compute_mode(file_size, count, etag)
-        chunk_size = compute_chunk(file_size)
-        part_size = (file_size.to_f / count).ceil
-        if chunk_size < part_size
-          multithreaded_get_by_ranges(file_size, etag)
-        else
-          multithreaded_get_by_parts(count, file_size, etag)
+      def multithreaded_get_by_parts(total_parts, file_size, etag, opts)
+        parts = (1..total_parts).map do |part|
+          params = get_opts(opts[:params].merge(part_number: part, if_match: etag))
+          Part.new(part_number: part, params: params)
         end
+        download_with_executor(PartList.new(parts), file_size, opts)
       end
 
-      def compute_chunk(file_size)
-        raise ArgumentError, ":chunk_size shouldn't exceed total file size." if @chunk_size && @chunk_size > file_size
-
-        @chunk_size || [(file_size.to_f / MAX_PARTS).ceil, MIN_CHUNK_SIZE].max.to_i
-      end
-
-      def multithreaded_get_by_ranges(file_size, etag)
+      def multithreaded_get_by_ranges(file_size, etag, opts)
         offset = 0
-        default_chunk_size = compute_chunk(file_size)
+        default_chunk_size = compute_chunk(opts[:chunk_size], file_size)
         chunks = []
         part_number = 1 # parts start at 1
         while offset < file_size
           progress = offset + default_chunk_size
           progress = file_size if progress > file_size
-          params = @params.merge(range: "bytes=#{offset}-#{progress - 1}", if_match: etag)
+          params = get_opts(opts[:params].merge(range: "bytes=#{offset}-#{progress - 1}", if_match: etag))
           chunks << Part.new(part_number: part_number, size: (progress - offset), params: params)
           part_number += 1
           offset = progress
         end
-        download_in_threads(PartList.new(chunks), file_size)
-      end
-
-      def multithreaded_get_by_parts(n_parts, total_size, etag)
-        parts = (1..n_parts).map do |part|
-          Part.new(part_number: part, params: @params.merge(part_number: part, if_match: etag))
-        end
-        download_in_threads(PartList.new(parts), total_size)
-      end
-
-      def download_in_threads(pending, total_size)
-        threads = []
-        progress = MultipartProgress.new(pending, total_size, @progress_callback) if @progress_callback
-        unless [File, Tempfile].include?(@destination.class)
-          @temp_path = "#{@destination}.s3tmp.#{SecureRandom.alphanumeric(8)}"
-        end
-        @thread_count.times do
-          thread = Thread.new do
-            begin
-              while (part = pending.shift)
-                if progress
-                  part.params[:on_chunk_received] =
-                    proc do |_chunk, bytes, total|
-                      progress.call(part.part_number, bytes, total)
-                    end
-                end
-                resp = @client.get_object(part.params)
-                range = extract_range(resp.content_range)
-                validate_range(range, part.params[:range]) if part.params[:range]
-                write(resp.body, range)
-                if @on_checksum_validated && resp.checksum_validated
-                  @on_checksum_validated.call(resp.checksum_validated, resp)
-                end
-              end
-              nil
-            rescue StandardError => e
-              pending.clear! # keep other threads from downloading other parts
-              raise e
-            end
-          end
-          threads << thread
-        end
-        threads.map(&:value).compact
+        download_with_executor(PartList.new(chunks), file_size, opts)
       end
 
-      def extract_range(value)
-        value.match(%r{bytes (?<range>\d+-\d+)/\d+})[:range]
+      def range_request(opts)
+        resp = @client.head_object(head_opts(opts[:params]))
+        resolve_temp_path(opts)
+        multithreaded_get_by_ranges(resp.content_length, resp.etag, opts)
       end
 
-      def validate_range(actual, expected)
-        return if actual == expected.match(/bytes=(?<range>\d+-\d+)/)[:range]
+      def resolve_temp_path(opts)
+        return if [File, Tempfile].include?(opts[:destination].class)
 
-        raise MultipartDownloadError, "multipart download failed: expected range of #{expected} but got #{actual}"
+        opts[:temp_path] ||= "#{opts[:destination]}.s3tmp.#{SecureRandom.alphanumeric(8)}"
       end
 
-      def write(body, range)
-        path = @temp_path || @destination
-        File.write(path, body.read, range.split('-').first.to_i)
-      end
-
-      def single_request
-        params = @params.merge(response_target: @destination)
-        params[:on_chunk_received] = single_part_progress if @progress_callback
+      def single_request(opts)
+        params = get_opts(opts[:params]).merge(response_target: opts[:destination])
+        params[:on_chunk_received] = single_part_progress(opts) if opts[:progress_callback]
         resp = @client.get_object(params)
-        return resp unless @on_checksum_validated
+        return resp unless opts[:on_checksum_validated]
 
-        @on_checksum_validated.call(resp.checksum_validated, resp) if resp.checksum_validated
+        opts[:on_checksum_validated].call(resp.checksum_validated, resp) if resp.checksum_validated
         resp
       end
 
-      def single_part_progress
+      def single_part_progress(opts)
         proc do |_chunk, bytes_read, total_size|
-          @progress_callback.call([bytes_read], [total_size], total_size)
+          opts[:progress_callback].call([bytes_read], [total_size], total_size)
+        end
+      end
+
+      def update_progress(progress, part)
+        part.params[:on_chunk_received] =
+          proc do |_chunk, bytes, total|
+            progress.call(part.part_number, bytes, total)
+          end
+      end
+
+      def validate_destination!(destination)
+        valid_types = [String, Pathname, File, Tempfile]
+        return if valid_types.include?(destination.class)
+
+        raise ArgumentError, "Invalid destination, expected #{valid_types.join(', ')} but got: #{destination.class}"
+      end
+
+      def validate_opts!(opts)
+        if opts[:on_checksum_validated] && !opts[:on_checksum_validated].respond_to?(:call)
+          raise ArgumentError, ':on_checksum_validated must be callable'
+        end
+
+        valid_modes = %w[auto get_range single_request]
+        unless valid_modes.include?(opts[:mode])
+          msg = "Invalid mode #{opts[:mode]} provided, :mode should be single_request, get_range or auto"
+          raise ArgumentError, msg
+        end
+
+        if opts[:mode] == 'get_range' && opts[:chunk_size].nil?
+          raise ArgumentError, 'In get_range mode, :chunk_size must be provided'
+        end
+
+        if opts[:chunk_size] && opts[:chunk_size] <= 0
+          raise ArgumentError, ':chunk_size must be positive'
         end
       end
 
+      def validate_range(actual, expected)
+        return if actual == expected.match(/bytes=(?<range>\d+-\d+)/)[:range]
+
+        raise MultipartDownloadError, "multipart download failed: expected range of #{expected} but got #{actual}"
+      end
+
+      def write(body, range, opts)
+        path = opts[:temp_path] || opts[:destination]
+        File.write(path, body.read, range.split('-').first.to_i)
+      end
+
       # @api private
       class Part < Struct.new(:part_number, :size, :params)
         include Aws::Structure
diff --git a/gems/aws-sdk-s3/lib/aws-sdk-s3/file_uploader.rb b/gems/aws-sdk-s3/lib/aws-sdk-s3/file_uploader.rb
index 587066551ea..62dbb07f8c3 100644
--- a/gems/aws-sdk-s3/lib/aws-sdk-s3/file_uploader.rb
+++ b/gems/aws-sdk-s3/lib/aws-sdk-s3/file_uploader.rb
@@ -13,8 +13,8 @@ class FileUploader
       # @option options [Client] :client
       # @option options [Integer] :multipart_threshold (104857600)
       def initialize(options = {})
-        @options = options
         @client = options[:client] || Client.new
+        @executor = options[:executor]
         @multipart_threshold = options[:multipart_threshold] || DEFAULT_MULTIPART_THRESHOLD
       end
 
@@ -36,11 +36,9 @@ def initialize(options = {})
       # @return [void]
       def upload(source, options = {})
         Aws::Plugins::UserAgent.metric('S3_TRANSFER') do
-          if File.size(source) >= multipart_threshold
-            MultipartFileUploader.new(@options).upload(source, options)
+          if File.size(source) >= @multipart_threshold
+            MultipartFileUploader.new(client: @client, executor: @executor).upload(source, options)
           else
-            # remove multipart parameters not supported by put_object
-            options.delete(:thread_count)
             put_object(source, options)
           end
         end
@@ -48,9 +46,9 @@ def upload(source, options = {})
 
       private
 
-      def open_file(source)
-        if String === source || Pathname === source
-          File.open(source, 'rb') { |file| yield(file) }
+      def open_file(source, &block)
+        if source.is_a?(String) || source.is_a?(Pathname)
+          File.open(source, 'rb', &block)
         else
           yield(source)
         end
diff --git a/gems/aws-sdk-s3/lib/aws-sdk-s3/multipart_file_uploader.rb b/gems/aws-sdk-s3/lib/aws-sdk-s3/multipart_file_uploader.rb
index bcc05f1fc9e..bab023e1bf7 100644
--- a/gems/aws-sdk-s3/lib/aws-sdk-s3/multipart_file_uploader.rb
+++ b/gems/aws-sdk-s3/lib/aws-sdk-s3/multipart_file_uploader.rb
@@ -7,7 +7,6 @@ module Aws
   module S3
     # @api private
     class MultipartFileUploader
-
       MIN_PART_SIZE = 5 * 1024 * 1024 # 5MB
       MAX_PARTS = 10_000
       DEFAULT_THREAD_COUNT = 10
@@ -21,10 +20,9 @@ class MultipartFileUploader
       )
 
       # @option options [Client] :client
-      # @option options [Integer] :thread_count (DEFAULT_THREAD_COUNT)
       def initialize(options = {})
         @client = options[:client] || Client.new
-        @thread_count = options[:thread_count] || DEFAULT_THREAD_COUNT
+        @executor = options[:executor]
       end
 
       # @return [Client]
@@ -38,11 +36,12 @@ def initialize(options = {})
       #   It will be invoked with [bytes_read], [total_sizes]
       # @return [Seahorse::Client::Response] - the CompleteMultipartUploadResponse
       def upload(source, options = {})
-        raise ArgumentError, 'unable to multipart upload files smaller than 5MB' if File.size(source) < MIN_PART_SIZE
+        file_size = File.size(source)
+        raise ArgumentError, 'unable to multipart upload files smaller than 5MB' if file_size < MIN_PART_SIZE
 
         upload_id = initiate_upload(options)
-        parts = upload_parts(upload_id, source, options)
-        complete_upload(upload_id, parts, source, options)
+        parts = upload_parts(upload_id, source, file_size, options)
+        complete_upload(upload_id, parts, file_size, options)
       end
 
       private
@@ -51,22 +50,22 @@ def initiate_upload(options)
         @client.create_multipart_upload(create_opts(options)).upload_id
       end
 
-      def complete_upload(upload_id, parts, source, options)
+      def complete_upload(upload_id, parts, file_size, options)
         @client.complete_multipart_upload(
           **complete_opts(options).merge(
             upload_id: upload_id,
             multipart_upload: { parts: parts },
-            mpu_object_size: File.size(source)
+            mpu_object_size: file_size
           )
         )
       rescue StandardError => e
         abort_upload(upload_id, options, [e])
       end
 
-      def upload_parts(upload_id, source, options)
+      def upload_parts(upload_id, source, file_size, options)
         completed = PartList.new
-        pending = PartList.new(compute_parts(upload_id, source, options))
-        errors = upload_in_threads(pending, completed, options)
+        pending = PartList.new(compute_parts(upload_id, source, file_size, options))
+        errors = upload_with_executor(pending, completed, options)
         if errors.empty?
           completed.to_a.sort_by { |part| part[:part_number] }
         else
@@ -86,17 +85,20 @@ def abort_upload(upload_id, options, errors)
         raise MultipartUploadError.new(msg, errors + [e])
       end
 
-      def compute_parts(upload_id, source, options)
-        size = File.size(source)
-        default_part_size = compute_default_part_size(size)
+      def compute_parts(upload_id, source, file_size, options)
+        default_part_size = compute_default_part_size(file_size)
         offset = 0
         part_number = 1
         parts = []
-        while offset < size
+        while offset < file_size
           parts << upload_part_opts(options).merge(
             upload_id: upload_id,
             part_number: part_number,
-            body: FilePart.new(source: source, offset: offset, size: part_size(size, default_part_size, offset))
+            body: FilePart.new(
+              source: source,
+              offset: offset,
+              size: part_size(file_size, default_part_size, offset)
+            )
           )
           part_number += 1
           offset += default_part_size
@@ -108,24 +110,20 @@ def checksum_key?(key)
         CHECKSUM_KEYS.include?(key)
       end
 
-      def has_checksum_key?(keys)
+      def has_checksum_keys?(keys)
         keys.any? { |key| checksum_key?(key) }
       end
 
       def create_opts(options)
         opts = { checksum_algorithm: Aws::Plugins::ChecksumAlgorithm::DEFAULT_CHECKSUM }
-        opts[:checksum_type] = 'FULL_OBJECT' if has_checksum_key?(options.keys)
-        CREATE_OPTIONS.each_with_object(opts) do |key, hash|
-          hash[key] = options[key] if options.key?(key)
-        end
+        opts[:checksum_type] = 'FULL_OBJECT' if has_checksum_keys?(options.keys)
+        CREATE_OPTIONS.each_with_object(opts) { |k, h| h[k] = options[k] if options.key?(k) }
       end
 
       def complete_opts(options)
         opts = {}
-        opts[:checksum_type] = 'FULL_OBJECT' if has_checksum_key?(options.keys)
-        COMPLETE_OPTIONS.each_with_object(opts) do |key, hash|
-          hash[key] = options[key] if options.key?(key)
-        end
+        opts[:checksum_type] = 'FULL_OBJECT' if has_checksum_keys?(options.keys)
+        COMPLETE_OPTIONS.each_with_object(opts) { |k, h| h[k] = options[k] if options.key?(k) }
       end
 
       def upload_part_opts(options)
@@ -135,43 +133,43 @@ def upload_part_opts(options)
         end
       end
 
-      def upload_in_threads(pending, completed, options)
-        threads = []
+      def upload_with_executor(pending, completed, options)
+        upload_attempts = 0
+        completion_queue = Queue.new
+        abort_upload = false
+        errors = []
+
         if (callback = options[:progress_callback])
           progress = MultipartProgress.new(pending, callback)
         end
-        options.fetch(:thread_count, @thread_count).times do
-          thread = Thread.new do
-            begin
-              while (part = pending.shift)
-                if progress
-                  part[:on_chunk_sent] =
-                    proc do |_chunk, bytes, _total|
-                      progress.call(part[:part_number], bytes)
-                    end
-                end
-                resp = @client.upload_part(part)
-                part[:body].close
-                completed_part = { etag: resp.etag, part_number: part[:part_number] }
-                algorithm = resp.context.params[:checksum_algorithm]
-                k = "checksum_#{algorithm.downcase}".to_sym
-                completed_part[k] = resp.send(k)
-                completed.push(completed_part)
-              end
-              nil
-            rescue StandardError => e
-              # keep other threads from uploading other parts
-              pending.clear!
-              e
-            end
+
+        while (part = pending.shift)
+          break if abort_upload
+
+          upload_attempts += 1
+          @executor.post(part) do |p|
+            update_progress(progress, p) if progress
+            resp = @client.upload_part(p)
+            p[:body].close
+            completed_part = { etag: resp.etag, part_number: p[:part_number] }
+            algorithm = resp.context.params[:checksum_algorithm].downcase
+            k = "checksum_#{algorithm}".to_sym
+            completed_part[k] = resp.send(k)
+            completed.push(completed_part)
+          rescue StandardError => e
+            abort_upload = true
+            errors << e
+          ensure
+            completion_queue << :done
           end
-          threads << thread
         end
-        threads.map(&:value).compact
+
+        upload_attempts.times { completion_queue.pop }
+        errors
       end
 
-      def compute_default_part_size(source_size)
-        [(source_size.to_f / MAX_PARTS).ceil, MIN_PART_SIZE].max.to_i
+      def compute_default_part_size(file_size)
+        [(file_size.to_f / MAX_PARTS).ceil, MIN_PART_SIZE].max.to_i
       end
 
       def part_size(total_size, part_size, offset)
@@ -182,6 +180,13 @@ def part_size(total_size, part_size, offset)
         end
       end
 
+      def update_progress(progress, part)
+        part[:on_chunk_sent] =
+          proc do |_chunk, bytes, _total|
+            progress.call(part[:part_number], bytes)
+          end
+      end
+
       # @api private
       class PartList
         def initialize(parts = [])
diff --git a/gems/aws-sdk-s3/lib/aws-sdk-s3/transfer_manager.rb b/gems/aws-sdk-s3/lib/aws-sdk-s3/transfer_manager.rb
index 03bd249d5e2..7f925cc0ba1 100644
--- a/gems/aws-sdk-s3/lib/aws-sdk-s3/transfer_manager.rb
+++ b/gems/aws-sdk-s3/lib/aws-sdk-s3/transfer_manager.rb
@@ -18,11 +18,15 @@ class TransferManager
       #   will be created automatically.
       def initialize(options = {})
         @client = options.delete(:client) || Client.new
+        @executor = options.delete(:executor)
       end
 
       # @return [S3::Client]
       attr_reader :client
 
+      # @return [Object] executor
+      attr_reader :executor
+
       # Downloads a file in S3 to a path on disk.
       #
       #     # small files (< 5MB) are downloaded in a single API call
@@ -107,6 +111,11 @@ def download_file(destination, bucket:, key:, **options)
         true
       end
 
+      # TODO: Docs
+      def download_directory(destination, bucket:, **options)
+        # TODO
+      end
+
       # Uploads a file from disk to S3.
       #
       #     # a small file are uploaded with PutObject API
@@ -178,13 +187,19 @@ def upload_file(source, bucket:, key:, **options)
         uploading_options = options.dup
         uploader = FileUploader.new(
           multipart_threshold: uploading_options.delete(:multipart_threshold),
-          client: @client
+          client: @client,
+          executor: @executor
         )
         response = uploader.upload(source, uploading_options.merge(bucket: bucket, key: key))
         yield response if block_given?
         true
       end
 
+      # TODO: Docs
+      def upload_directory(source, bucket:, **options)
+        # TODO
+      end
+
       # Uploads a stream in a streaming fashion to S3.
       #
       # Passed chunks automatically split into multipart upload parts and the parts are uploaded in parallel.
@@ -248,5 +263,6 @@ def upload_stream(bucket:, key:, **options, &block)
         true
       end
     end
+
   end
 end
diff --git a/gems/aws-sdk-s3/spec/file_downloader_spec.rb b/gems/aws-sdk-s3/spec/file_downloader_spec.rb
index 0f3dd8fb2cf..2632377b981 100644
--- a/gems/aws-sdk-s3/spec/file_downloader_spec.rb
+++ b/gems/aws-sdk-s3/spec/file_downloader_spec.rb
@@ -7,7 +7,8 @@ module Aws
   module S3
     describe FileDownloader do
       let(:client) { S3::Client.new(stub_responses: true) }
-      let(:subject) { FileDownloader.new(client: client) }
+      let(:executor) { DefaultExecutor.new }
+      let(:subject) { FileDownloader.new(client: client, executor: executor) }
       let(:tmpdir) { Dir.tmpdir }
 
       describe '#initialize' do
@@ -198,7 +199,6 @@ module S3
 
           it 'raises when checksum validation fails on multipart object' do
             client.stub_responses(:get_object, { body: 'body', checksum_sha1: 'invalid' })
-            expect(Thread).to receive(:new).and_yield.and_return(double(value: nil))
             expect { subject.download(path, parts_params) }.to raise_error(Aws::Errors::ChecksumError)
           end
 
@@ -208,7 +208,6 @@ module S3
               expect(ctx.params[:if_match]).to eq('test-etag')
               'PreconditionFailed'
             })
-            expect(Thread).to receive(:new).and_yield.and_return(double(value: nil))
             expect { subject.download(path, range_params.merge(chunk_size: one_meg, mode: 'get_range')) }
               .to raise_error(Aws::S3::Errors::PreconditionFailed)
           end
@@ -219,8 +218,6 @@ module S3
               expect(ctx.params[:if_match]).to eq('test-etag')
               'PreconditionFailed'
             })
-
-            expect(Thread).to receive(:new).and_yield.and_return(double(value: nil))
             expect { subject.download(path, parts_params) }.to raise_error(Aws::S3::Errors::PreconditionFailed)
           end
 
@@ -246,7 +243,6 @@ module S3
 
           it 'raises when range validation fails' do
             client.stub_responses(:get_object, { body: 'body', content_range: 'bytes 0-3/4' })
-            expect(Thread).to receive(:new).and_yield.and_return(double(value: nil))
             expect { subject.download(path, range_params.merge(mode: 'get_range', chunk_size: one_meg)) }
               .to raise_error(Aws::S3::MultipartDownloadError)
           end
@@ -263,7 +259,6 @@ module S3
               responses[context.params[:range]]
             })
 
-            expect(Thread).to receive(:new).and_yield.and_return(double(value: nil))
             expect { subject.download(path, range_params.merge(chunk_size: 5 * one_meg, mode: 'get_range')) }
               .to raise_error(Aws::S3::MultipartDownloadError)
             expect(File.exist?(path)).to be(true)
diff --git a/gems/aws-sdk-s3/spec/file_uploader_spec.rb b/gems/aws-sdk-s3/spec/file_uploader_spec.rb
index 64dbaf7cdd2..dc3ab94b052 100644
--- a/gems/aws-sdk-s3/spec/file_uploader_spec.rb
+++ b/gems/aws-sdk-s3/spec/file_uploader_spec.rb
@@ -81,12 +81,6 @@ module S3
 
           subject.upload(ten_meg_file.path, params)
         end
-
-        it 'does not fail when given :thread_count' do
-          expect(client).to receive(:put_object).with(params.merge(body: ten_meg_file))
-
-          subject.upload(ten_meg_file, params.merge(thread_count: 1))
-        end
       end
     end
   end
diff --git a/gems/aws-sdk-s3/spec/multipart_file_uploader_spec.rb b/gems/aws-sdk-s3/spec/multipart_file_uploader_spec.rb
index 82e147986e3..54b50a13a01 100644
--- a/gems/aws-sdk-s3/spec/multipart_file_uploader_spec.rb
+++ b/gems/aws-sdk-s3/spec/multipart_file_uploader_spec.rb
@@ -7,7 +7,8 @@ module Aws
   module S3
     describe MultipartFileUploader do
       let(:client) { S3::Client.new(stub_responses: true) }
-      let(:subject) { MultipartFileUploader.new(client: client) }
+      let(:executor) { DefaultExecutor.new }
+      let(:subject) { MultipartFileUploader.new(client: client, executor: executor) }
       let(:params) { { bucket: 'bucket', key: 'key' } }
 
       describe '#initialize' do
@@ -85,7 +86,6 @@ module S3
         end
 
         it 'reports progress for multipart uploads' do
-          allow(Thread).to receive(:new).and_yield.and_return(double(value: nil))
           client.stub_responses(:create_multipart_upload, upload_id: 'id')
           client.stub_responses(:complete_multipart_upload)
           expect(client).to receive(:upload_part).exactly(24).times do |args|
@@ -127,10 +127,6 @@ module S3
         end
 
         it 'reports when it is unable to abort a failed multipart upload' do
-          allow(Thread).to receive(:new) do |_, &block|
-            double(value: block.call)
-          end
-
           client.stub_responses(
             :upload_part,
             [