diff --git a/include/bluetooth/audio/csis.h b/include/bluetooth/audio/csis.h
index 1e954bf01cc..d609ef74089 100644
--- a/include/bluetooth/audio/csis.h
+++ b/include/bluetooth/audio/csis.h
@@ -292,14 +292,15 @@ void bt_csis_client_register_cb(struct bt_csis_client_cb *cb);
 
 /**
  * @brief Read the lock value of a specific device and instance.
- *
- * @param conn      Pointer to the connection to the device.
- * @param inst_idx  Index of the CSIS index of the peer device (as it may have
- *                  multiple CSIS instances).
+
+ * @param members   Member to get the lock value from
+ * @param set       Pointer to the specific set of the @p member to get the
+ *                  lock value from.
  *
  * @return Return 0 on success, or an errno value on error.
  */
-int bt_csis_client_lock_get(struct bt_conn *conn, uint8_t inst_idx);
+int bt_csis_client_lock_get(struct bt_csis_client_set_member *member,
+			    const struct bt_csis_client_set *set);
 
 /**
  * @brief Lock an array of set members
diff --git a/subsys/bluetooth/audio/csis_client.c b/subsys/bluetooth/audio/csis_client.c
index 698a4b02fcd..239cdb76ec6 100644
--- a/subsys/bluetooth/audio/csis_client.c
+++ b/subsys/bluetooth/audio/csis_client.c
@@ -1195,25 +1195,23 @@ int bt_csis_client_discover_sets(struct bt_csis_client_set_member *member)
 	return err;
 }
 
-int bt_csis_client_lock_get(struct bt_conn *conn, uint8_t inst_idx)
+int bt_csis_client_lock_get(struct bt_csis_client_set_member *member,
+			    const struct bt_csis_client_set *set)
 {
 	int err;
 
-	if (inst_idx >= CONFIG_BT_CSIS_CLIENT_MAX_CSIS_INSTANCES) {
-		BT_DBG("Invalid index %u", inst_idx);
-		return -EINVAL;
-	} else if (busy) {
+	if (busy) {
 		BT_DBG("csis_client busy");
 		return -EBUSY;
 	} else if (cur_inst != NULL) {
-		if (cur_inst != lookup_instance_by_index(conn, inst_idx)) {
+		if (cur_inst != set->csis) {
 			BT_DBG("csis_client busy with current instance");
 			return -EBUSY;
 		}
 	} else {
-		cur_inst = lookup_instance_by_index(conn, inst_idx);
+		cur_inst = set->csis;
 		if (cur_inst == NULL) {
-			BT_DBG("Inst not found");
+			BT_DBG("set->csis is NULL");
 			return -EINVAL;
 		}
 	}
@@ -1229,7 +1227,7 @@ int bt_csis_client_lock_get(struct bt_conn *conn, uint8_t inst_idx)
 	read_params.single.handle = cur_inst->cli.set_lock_handle;
 	read_params.single.offset = 0U;
 
-	err = bt_gatt_read(conn, &read_params);
+	err = bt_gatt_read(member->conn, &read_params);
 
 	if (err != 0) {
 		cur_inst = NULL;
diff --git a/subsys/bluetooth/shell/csis_client.c b/subsys/bluetooth/shell/csis_client.c
index 17ea7d658f3..1418077c553 100644
--- a/subsys/bluetooth/shell/csis_client.c
+++ b/subsys/bluetooth/shell/csis_client.c
@@ -419,8 +419,8 @@ static int cmd_csis_client_lock_get(const struct shell *sh, size_t argc,
 		}
 	}
 
-	err = bt_csis_client_lock_get(set_members[member_index].conn,
-				      (uint8_t)idx);
+	err = bt_csis_client_lock_get(&set_members[member_index],
+				      &set_members[member_index].sets[idx]);
 	if (err != 0) {
 		shell_error(sh, "Fail: %d", err);
 	}