diff --git a/tests/net/lib/coap_client/CMakeLists.txt b/tests/net/lib/coap_client/CMakeLists.txt
index 60506c23c2d3f3..9486b914706eb2 100644
--- a/tests/net/lib/coap_client/CMakeLists.txt
+++ b/tests/net/lib/coap_client/CMakeLists.txt
@@ -24,5 +24,6 @@ add_compile_definitions(CONFIG_COAP_CLIENT_MESSAGE_HEADER_SIZE=48)
 add_compile_definitions(CONFIG_COAP_CLIENT_STACK_SIZE=1024)
 add_compile_definitions(CONFIG_COAP_CLIENT_THREAD_PRIORITY=10)
 add_compile_definitions(CONFIG_COAP_LOG_LEVEL=4)
-add_compile_definitions(CONFIG_NET_SOCKETS_POSIX_NAMES=y)
 add_compile_definitions(CONFIG_COAP_INIT_ACK_TIMEOUT_MS=2000)
+add_compile_definitions(CONFIG_COAP_CLIENT_MAX_REQUESTS=2)
+add_compile_definitions(CONFIG_COAP_CLIENT_MAX_INSTANCES=2)
diff --git a/tests/net/lib/coap_client/src/main.c b/tests/net/lib/coap_client/src/main.c
index cb77c7c0cfe36d..9e66015dbee0d4 100644
--- a/tests/net/lib/coap_client/src/main.c
+++ b/tests/net/lib/coap_client/src/main.c
@@ -17,7 +17,8 @@ DEFINE_FFF_GLOBALS;
 
 static uint8_t last_response_code;
 static const char *test_path = "test";
-static uint16_t last_message_id;
+
+static uint16_t messages_needing_response[2];
 
 static struct coap_client client;
 
@@ -33,11 +34,21 @@ static char *long_payload = "Lorem ipsum dolor sit amet, consectetur adipiscing
 static ssize_t z_impl_zsock_recvfrom_custom_fake(int sock, void *buf, size_t max_len, int flags,
 					  struct sockaddr *src_addr, socklen_t *addrlen)
 {
+	uint16_t last_message_id = 0;
+
 	LOG_INF("Recvfrom");
-	static uint8_t ack_data[] = {
+	uint8_t ack_data[] = {
 		0x68, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
 	};
 
+	if (messages_needing_response[0] != 0) {
+		last_message_id = messages_needing_response[0];
+		messages_needing_response[0] = 0;
+	} else {
+		last_message_id = messages_needing_response[1];
+		messages_needing_response[1] = 0;
+	}
+
 	ack_data[2] = (uint8_t) (last_message_id >> 8);
 	ack_data[3] = (uint8_t) last_message_id;
 
@@ -50,11 +61,17 @@ static ssize_t z_impl_zsock_sendto_custom_fake(int sock, void *buf, size_t len,
 			       int flags, const struct sockaddr *dest_addr,
 			       socklen_t addrlen)
 {
-	LOG_INF("Sendto");
-	last_message_id = 0;
+	uint16_t last_message_id = 0;
+
 	last_message_id |= ((uint8_t *) buf)[2] << 8;
 	last_message_id |= ((uint8_t *) buf)[3];
 
+	if (messages_needing_response[0] == 0) {
+		messages_needing_response[0] = last_message_id;
+	} else {
+		messages_needing_response[1] = last_message_id;
+	}
+
 	last_response_code = ((uint8_t *) buf)[1];
 
 	LOG_INF("Latest message ID: %d", last_message_id);
@@ -65,10 +82,20 @@ static ssize_t z_impl_zsock_recvfrom_custom_fake_response(int sock, void *buf, s
 							  int flags, struct sockaddr *src_addr,
 							  socklen_t *addrlen)
 {
+	uint16_t last_message_id = 0;
+
 	static uint8_t ack_data[] = {
 		0x48, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
 	};
 
+	if (messages_needing_response[0] != 0) {
+		last_message_id = messages_needing_response[0];
+		messages_needing_response[0] = 0;
+	} else {
+		last_message_id = messages_needing_response[1];
+		messages_needing_response[1] = 0;
+	}
+
 	ack_data[2] = (uint8_t) (last_message_id >> 8);
 	ack_data[3] = (uint8_t) last_message_id;
 
@@ -81,10 +108,20 @@ static ssize_t z_impl_zsock_recvfrom_custom_fake_empty_ack(int sock, void *buf,
 							   int flags, struct sockaddr *src_addr,
 							   socklen_t *addrlen)
 {
+	uint16_t last_message_id = 0;
+
 	static uint8_t ack_data[] = {
 		0x68, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
 	};
 
+	if (messages_needing_response[0] != 0) {
+		last_message_id = messages_needing_response[0];
+		messages_needing_response[0] = 0;
+	} else {
+		last_message_id = messages_needing_response[1];
+		messages_needing_response[1] = 0;
+	}
+
 	ack_data[2] = (uint8_t) (last_message_id >> 8);
 	ack_data[3] = (uint8_t) last_message_id;
 
@@ -99,10 +136,20 @@ static ssize_t z_impl_zsock_recvfrom_custom_fake_unmatching(int sock, void *buf,
 							    int flags, struct sockaddr *src_addr,
 							    socklen_t *addrlen)
 {
+	uint16_t last_message_id = 0;
+
 	static uint8_t ack_data[] = {
 		0x68, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01
 	};
 
+	if (messages_needing_response[0] != 0) {
+		last_message_id = messages_needing_response[0];
+		messages_needing_response[0] = 0;
+	} else {
+		last_message_id = messages_needing_response[1];
+		messages_needing_response[1] = 0;
+	}
+
 	ack_data[2] = (uint8_t) (last_message_id >> 8);
 	ack_data[3] = (uint8_t) last_message_id;
 
@@ -242,7 +289,7 @@ ZTEST(coap_client, test_no_response)
 
 	LOG_INF("Send request");
 	clear_socket_events();
-	ret = coap_client_req(&client, 0, &address, &client_request, -1);
+	ret = coap_client_req(&client, 0, &address, &client_request, 0);
 
 	zassert_true(ret >= 0, "Sending request failed, %d", ret);
 	k_sleep(K_MSEC(1000));
@@ -307,15 +354,12 @@ ZTEST(coap_client, test_multiple_requests)
 	zassert_true(ret >= 0, "Sending request failed, %d", ret);
 
 	ret = coap_client_req(&client, 0, &address, &client_request, -1);
-	zassert_equal(ret, -EAGAIN, "Shouldn't be able to send 2 requests at same time");
+	zassert_true(ret >= 0, "Sending request failed, %d", ret);
 
 	k_sleep(K_MSEC(5));
 	k_sleep(K_MSEC(1000));
 	zassert_equal(last_response_code, COAP_RESPONSE_CODE_OK, "Unexpected response");
 
-	ret = coap_client_req(&client, 0, &address, &client_request, -1);
-	zassert_true(ret >= 0, "Sending request failed, %d", ret);
-
 	k_sleep(K_MSEC(5));
 	k_sleep(K_MSEC(1000));
 	zassert_equal(last_response_code, COAP_RESPONSE_CODE_OK, "Unexpected response");