diff --git a/samples/net/mqtt_sn_publisher/prj.conf b/samples/net/mqtt_sn_publisher/prj.conf
index 405b9dc3c40d1..57bc17868f1ef 100644
--- a/samples/net/mqtt_sn_publisher/prj.conf
+++ b/samples/net/mqtt_sn_publisher/prj.conf
@@ -37,7 +37,6 @@ CONFIG_NET_CONFIG_MY_IPV4_ADDR="192.0.2.1"
 CONFIG_MQTT_SN_LIB=y
 CONFIG_MQTT_SN_TRANSPORT_UDP=y
 CONFIG_MQTT_SN_LIB_BROADCAST_RADIUS=1
-CONFIG_MQTT_SN_LIB_MAX_ADDR_SIZE=24
 CONFIG_NET_SAMPLE_MQTT_SN_STATIC_GATEWAY=y
 CONFIG_NET_SAMPLE_MQTT_SN_GATEWAY_ADDRESS="192.0.2.2:10000"
 CONFIG_NET_SAMPLE_MQTT_SN_BROADCAST_ADDRESS="225.1.1.1:1883"
diff --git a/subsys/net/lib/mqtt_sn/Kconfig b/subsys/net/lib/mqtt_sn/Kconfig
index c6265c556927f..5702fc807c706 100644
--- a/subsys/net/lib/mqtt_sn/Kconfig
+++ b/subsys/net/lib/mqtt_sn/Kconfig
@@ -38,6 +38,8 @@ config MQTT_SN_LIB_MAX_GATEWAYS
 
 config MQTT_SN_LIB_MAX_ADDR_SIZE
 	int "Maximum address size for the transport"
+	default 24 if NET_IPV6
+	default 8 if NET_IPV4
 	default 21
 	range 1 $(UINT8_MAX)
 	help
@@ -45,6 +47,11 @@ config MQTT_SN_LIB_MAX_ADDR_SIZE
 	  needs to know how long your addresses are. Set this to the maximum
 	  length in bytes of the address data structure for your implemented transport.
 
+	  A UDP transport requires at least 8 bytes on IPv4 and 24 bytes on
+	  IPv6, corresponding to the sizes of the sockaddr_in and sockaddr_in6
+	  structs. For an out-of-tree transport, you may need to adjust this
+	  value.
+
 config MQTT_SN_LIB_BROADCAST_RADIUS
 	int "Radius for broadcast messages"
 	default 1
diff --git a/subsys/net/lib/mqtt_sn/mqtt_sn_transport_udp.c b/subsys/net/lib/mqtt_sn/mqtt_sn_transport_udp.c
index 471a0135a31b9..d9a8ef2be3cf9 100644
--- a/subsys/net/lib/mqtt_sn/mqtt_sn_transport_udp.c
+++ b/subsys/net/lib/mqtt_sn/mqtt_sn_transport_udp.c
@@ -19,6 +19,12 @@
 #include <zephyr/logging/log.h>
 LOG_MODULE_DECLARE(net_mqtt_sn, CONFIG_MQTT_SN_LOG_LEVEL);
 
+BUILD_ASSERT(CONFIG_MQTT_SN_LIB_MAX_ADDR_SIZE >= sizeof(struct net_sockaddr_in) ||
+	     !IS_ENABLED(CONFIG_NET_IPV4));
+
+BUILD_ASSERT(CONFIG_MQTT_SN_LIB_MAX_ADDR_SIZE >= sizeof(struct net_sockaddr_in6) ||
+	     !IS_ENABLED(CONFIG_NET_IPV6));
+
 static char *get_ip_str(const struct net_sockaddr *sa, char *s, size_t maxlen)
 {
 	switch (sa->sa_family) {