diff --git a/waypoint.c b/waypoint.c
--- a/waypoint.c
+++ b/waypoint.c
@@ -319,7 +319,7 @@ int32 CmdRenameWaypoint(TileIndex tile, 
 {
 	Waypoint *wp;
 
-	if (!IsWaypointIndex(p1)) return CMD_ERROR;
+	if (!IsValidWaypointID(p1)) return CMD_ERROR;
 
 	if (_cmd_text[0] != '\0') {
 		StringID str = AllocateNameUnique(_cmd_text, 0);