diff --git a/PKHeX.Core/Legality/Areas/EncounterArea8g.cs b/PKHeX.Core/Legality/Areas/EncounterArea8g.cs
index 24d8f8d42..31e9e935d 100644
--- a/PKHeX.Core/Legality/Areas/EncounterArea8g.cs
+++ b/PKHeX.Core/Legality/Areas/EncounterArea8g.cs
@@ -106,6 +106,7 @@ namespace PKHeX.Core
             if (sf == default)
                 yield break;
 
+            var species = pkm.Species;
             var ball = (Ball)pkm.Ball;
             var met = Math.Max(sf.LevelMin, pkm.Met_Level);
             EncounterSlot8GO? deferredIV = null;
@@ -114,7 +115,7 @@ namespace PKHeX.Core
             {
                 if (!slot.IsLevelWithinRange(met))
                     continue;
-                if (!slot.IsBallValid(ball))
+                if (!slot.IsBallValid(ball, species))
                     continue;
                 if (!slot.Shiny.IsValid(pkm))
                     continue;
diff --git a/PKHeX.Core/Legality/Encounters/EncounterSlot/GO/EncounterSlot8GO.cs b/PKHeX.Core/Legality/Encounters/EncounterSlot/GO/EncounterSlot8GO.cs
index 8b77a4121..69cfc6a4b 100644
--- a/PKHeX.Core/Legality/Encounters/EncounterSlot/GO/EncounterSlot8GO.cs
+++ b/PKHeX.Core/Legality/Encounters/EncounterSlot/GO/EncounterSlot8GO.cs
@@ -26,7 +26,13 @@ namespace PKHeX.Core
         /// <summary>
         /// Checks if the <seealso cref="Ball"/> is compatible with the <seealso cref="PogoType"/>.
         /// </summary>
-        public bool IsBallValid(Ball ball) => Type.IsBallValid(ball);
+        public bool IsBallValid(Ball ball, int currentSpecies)
+        {
+            // GO does not natively produce Shedinja when evolving Nincada, and thus must be evolved in future games.
+            if (currentSpecies == (int)Core.Species.Shedinja && currentSpecies != Species)
+                return ball == Ball.Poke;
+            return Type.IsBallValid(ball);
+        }
 
         protected override void ApplyDetails(ITrainerInfo sav, EncounterCriteria criteria, PKM pk)
         {