diff --git a/subsys/modem/modem_cmux.c b/subsys/modem/modem_cmux.c
index d5547e03da28..30d80b3ec0bc 100644
--- a/subsys/modem/modem_cmux.c
+++ b/subsys/modem/modem_cmux.c
@@ -1108,26 +1108,29 @@ static int modem_cmux_dlci_pipe_api_transmit(void *data, const uint8_t *buf, siz
 {
 	struct modem_cmux_dlci *dlci = (struct modem_cmux_dlci *)data;
 	struct modem_cmux *cmux = dlci->cmux;
-	int ret = 0;
-
-	K_SPINLOCK(&cmux->work_lock) {
-		if (!cmux->attached) {
-			ret = -EPERM;
-			K_SPINLOCK_BREAK;
-		}
+	int ret;
 
-		struct modem_cmux_frame frame = {
-			.dlci_address = dlci->dlci_address,
-			.cr = true,
-			.pf = false,
-			.type = MODEM_CMUX_FRAME_TYPE_UIH,
-			.data = buf,
-			.data_len = size,
-		};
+	k_spinlock_key_t key = k_spin_lock(&cmux->work_lock);
 
-		ret = modem_cmux_transmit_data_frame(cmux, &frame);
+	if (!cmux->attached) {
+		ret = -EPERM;
+		k_spin_unlock(&cmux->work_lock, key);
+		return ret;
 	}
 
+	struct modem_cmux_frame frame = {
+		.dlci_address = dlci->dlci_address,
+		.cr = true,
+		.pf = false,
+		.type = MODEM_CMUX_FRAME_TYPE_UIH,
+		.data = buf,
+		.data_len = size,
+	};
+
+	ret = modem_cmux_transmit_data_frame(cmux, &frame);
+
+	k_spin_unlock(&cmux->work_lock, key);
+
 	return ret;
 }
 
diff --git a/subsys/modem/modem_pipelink.c b/subsys/modem/modem_pipelink.c
index e52d0117f62d..35faf9c3ad7a 100644
--- a/subsys/modem/modem_pipelink.c
+++ b/subsys/modem/modem_pipelink.c
@@ -29,9 +29,11 @@ bool modem_pipelink_is_connected(struct modem_pipelink *link)
 {
 	bool connected;
 
-	K_SPINLOCK(&link->spinlock) {
-		connected = link->connected;
-	}
+	k_spinlock_key_t key = k_spin_lock(&link->spinlock);
+
+	connected = link->connected;
+
+	k_spin_unlock(&link->spinlock, key);
 
 	return connected;
 }
diff --git a/subsys/modem/modem_stats.c b/subsys/modem/modem_stats.c
index e1790cb815a3..4b7fef1a0127 100644
--- a/subsys/modem/modem_stats.c
+++ b/subsys/modem/modem_stats.c
@@ -32,22 +32,26 @@ static void stats_buffer_list_append(struct modem_stats_buffer *buffer)
 
 static struct modem_stats_buffer *stats_buffer_list_first(void)
 {
-	struct modem_stats_buffer *first = NULL;
+	struct modem_stats_buffer *first;
 
-	K_SPINLOCK(&stats_buffer_lock) {
-		first = stats_buffer_from_node(sys_slist_peek_head(&stats_buffer_list));
-	}
+	k_spinlock_key_t key = k_spin_lock(&stats_buffer_lock);
+
+	first = stats_buffer_from_node(sys_slist_peek_head(&stats_buffer_list));
+
+	k_spin_unlock(&stats_buffer_lock, key);
 
 	return first;
 }
 
 static struct modem_stats_buffer *stats_buffer_list_next(struct modem_stats_buffer *buffer)
 {
-	struct modem_stats_buffer *next = NULL;
+	struct modem_stats_buffer *next;
 
-	K_SPINLOCK(&stats_buffer_lock) {
-		next = stats_buffer_from_node(sys_slist_peek_next(&buffer->node));
-	}
+	k_spinlock_key_t key = k_spin_lock(&stats_buffer_lock);
+
+	next = stats_buffer_from_node(sys_slist_peek_next(&buffer->node));
+
+	k_spin_unlock(&stats_buffer_lock, key);
 
 	return next;
 }