diff --git a/Data/Scripts/013_Overworld/011_PField_FieldMoves.rb b/Data/Scripts/013_Overworld/011_PField_FieldMoves.rb
index c7fd4150b..6695c6a1e 100644
--- a/Data/Scripts/013_Overworld/011_PField_FieldMoves.rb
+++ b/Data/Scripts/013_Overworld/011_PField_FieldMoves.rb
@@ -393,7 +393,7 @@ Events.onAction += proc { |_sender,_e|
           divemap = i; break
         end
       end
-      if PBTerrain.isDeepWater?($MapFactory.getTerrainTag(divemap,$game_player.x,$game_player.y))
+      if divemap && PBTerrain.isDeepWater?($MapFactory.getTerrainTag(divemap,$game_player.x,$game_player.y))
         pbSurfacing
       end
     end