diff --git a/drivers/mbox/mbox_nrf_bellboard_tx.c b/drivers/mbox/mbox_nrf_bellboard_tx.c
index e3f297623a6..9f98f57ff5d 100644
--- a/drivers/mbox/mbox_nrf_bellboard_tx.c
+++ b/drivers/mbox/mbox_nrf_bellboard_tx.c
@@ -23,7 +23,7 @@ static int bellboard_tx_send(const struct device *dev, uint32_t id, const struct
 	}
 
 	if (msg != NULL) {
-		return -ENOTSUP;
+		return -EMSGSIZE;
 	}
 
 	nrfy_bellboard_task_trigger(config->bellboard, nrf_bellboard_trigger_task_get(id));
diff --git a/drivers/mbox/mbox_nrf_vevif_event_tx.c b/drivers/mbox/mbox_nrf_vevif_event_tx.c
index e323a07bb7d..6a9e51aab50 100644
--- a/drivers/mbox/mbox_nrf_vevif_event_tx.c
+++ b/drivers/mbox/mbox_nrf_vevif_event_tx.c
@@ -38,7 +38,7 @@ static int vevif_event_tx_send(const struct device *dev, uint32_t id, const stru
 	}
 
 	if (msg != NULL) {
-		return -ENOTSUP;
+		return -EMSGSIZE;
 	}
 
 	nrf_vpr_csr_vevif_events_trigger(BIT(id));
diff --git a/drivers/mbox/mbox_nrf_vevif_task_tx.c b/drivers/mbox/mbox_nrf_vevif_task_tx.c
index 6aac7522617..191a94962d6 100644
--- a/drivers/mbox/mbox_nrf_vevif_task_tx.c
+++ b/drivers/mbox/mbox_nrf_vevif_task_tx.c
@@ -38,7 +38,7 @@ static int vevif_task_tx_send(const struct device *dev, uint32_t id, const struc
 	}
 
 	if (msg != NULL) {
-		return -ENOTSUP;
+		return -EMSGSIZE;
 	}
 
 	nrfy_vpr_task_trigger(config->vpr, nrfy_vpr_trigger_task_get(id));