diff --git a/samples/drivers/mbox/remote/src/main.c b/samples/drivers/mbox/remote/src/main.c
index ee2a26c41c3..4ff1a81f5bf 100644
--- a/samples/drivers/mbox/remote/src/main.c
+++ b/samples/drivers/mbox/remote/src/main.c
@@ -51,6 +51,12 @@ int main(void)
 	printk("Maximum TX channels: %d\n", mbox_max_channels_get_dt(&tx_channel));
 
 	while (1) {
+#if defined(CONFIG_MULTITHREADING)
+		k_sleep(K_MSEC(3000));
+#else
+		k_busy_wait(3000000);
+#endif
+
 		printk("Ping (on channel %d)\n", tx_channel.channel_id);
 
 		ret = mbox_send_dt(&tx_channel, NULL);
@@ -58,10 +64,7 @@ int main(void)
 			printk("Could not send (%d)\n", ret);
 			return 0;
 		}
-
-		k_sleep(K_MSEC(3000));
 	}
 #endif /* CONFIG_TX_ENABLED */
-
 	return 0;
 }
diff --git a/samples/drivers/mbox/sample.yaml b/samples/drivers/mbox/sample.yaml
index f4e4bc0f1de..40425495b38 100644
--- a/samples/drivers/mbox/sample.yaml
+++ b/samples/drivers/mbox/sample.yaml
@@ -78,3 +78,38 @@ tests:
       regex:
         - "Ping \\(on channel 16\\)"
         - "Pong \\(on channel 15\\)"
+
+  sample.drivers.mbox.nrf54l15_no_multithreading:
+    platform_allow:
+      - nrf54l15pdk/nrf54l15/cpuapp
+    integration_platforms:
+      - nrf54l15pdk/nrf54l15/cpuapp
+    extra_args:
+      mbox_SNIPPET=nordic-flpr
+      mbox_CONFIG_MULTITHREADING=n
+      remote_CONFIG_MULTITHREADING=n
+    sysbuild: true
+    harness: console
+    harness_config:
+      type: multi_line
+      ordered: false
+      regex:
+        - "Ping \\(on channel 16\\)"
+        - "Pong \\(on channel 15\\)"
+
+  sample.drivers.mbox.nrf54l15_remote_no_multithreading:
+    platform_allow:
+      - nrf54l15pdk/nrf54l15/cpuapp
+    integration_platforms:
+      - nrf54l15pdk/nrf54l15/cpuapp
+    extra_args:
+      mbox_SNIPPET=nordic-flpr
+      remote_CONFIG_MULTITHREADING=n
+    sysbuild: true
+    harness: console
+    harness_config:
+      type: multi_line
+      ordered: false
+      regex:
+        - "Ping \\(on channel 16\\)"
+        - "Pong \\(on channel 15\\)"
diff --git a/samples/drivers/mbox/src/main.c b/samples/drivers/mbox/src/main.c
index bf9690c868f..33430dcdd19 100644
--- a/samples/drivers/mbox/src/main.c
+++ b/samples/drivers/mbox/src/main.c
@@ -47,7 +47,11 @@ int main(void)
 	printk("Maximum TX channels: %d\n", mbox_max_channels_get_dt(&tx_channel));
 
 	while (1) {
+#if defined(CONFIG_MULTITHREADING)
 		k_sleep(K_MSEC(2000));
+#else
+		k_busy_wait(2000000);
+#endif
 
 		printk("Ping (on channel %d)\n", tx_channel.channel_id);