diff --git a/include/constants/pokemon.h b/include/constants/pokemon.h
index 224a3f892a..ba9495158a 100644
--- a/include/constants/pokemon.h
+++ b/include/constants/pokemon.h
@@ -395,4 +395,6 @@
 #define FLAG_GALARIAN_FORM      (1 << 4)
 #define FLAG_GENDER_DIFFERENCE  (1 << 5)
 
+#define LEGENDARY_PERFECT_IV_COUNT 3
+
 #endif // GUARD_CONSTANTS_POKEMON_H
diff --git a/include/constants/pokemon_config.h b/include/constants/pokemon_config.h
index 257c06b7c0..aafa898d90 100644
--- a/include/constants/pokemon_config.h
+++ b/include/constants/pokemon_config.h
@@ -17,6 +17,7 @@
 #define P_UPDATED_ABILITIES     GEN_8 // Since Gen 6, certain Pokémon have their abilities changed. Requires BATTLE_ENGINE for Gen4+ abilities.
 #define P_UPDATED_EGG_GROUPS    GEN_8 // Since Gen 8, certain Pokémon have gained new egg groups.
 #define P_SHEDINJA_BALL         GEN_8 // Since Gen 4, Shedinja requires a Poké Ball for its evolution. In Gen 3, Shedinja inherits Nincada's Ball.
+#define P_LEGENDARY_PERFECT_IVS GEN_8 // Since Gen 6, Legendaries, Mythicals and Ultra Beasts found in the wild or given through gifts have at least 3 perfect IVs.
 
 #define P_ENABLE_DEBUG          TRUE  // Enables a debug menu for pokemon sprites and icons, accessed by pressing SELECT in the summary screen.
 
diff --git a/src/pokemon.c b/src/pokemon.c
index f654dcf52a..5af93106a0 100644
--- a/src/pokemon.c
+++ b/src/pokemon.c
@@ -65,6 +65,7 @@ static bool8 ShouldGetStatBadgeBoost(u16 flagId, u8 battlerId);
 static u16 GiveMoveToBoxMon(struct BoxPokemon *boxMon, u16 move);
 static bool8 ShouldSkipFriendshipChange(void);
 static u8 SendMonToPC(struct Pokemon* mon);
+static void RemoveIVIndexFromList(u8 *ivs, u8 selectedIv);
 
 EWRAM_DATA static u8 sLearningMoveTableID = 0;
 EWRAM_DATA u8 gPlayerPartyCount = 0;
@@ -3204,6 +3205,9 @@ void CreateBoxMon(struct BoxPokemon *boxMon, u16 species, u8 level, u8 fixedIV,
     u32 personality;
     u32 value;
     u16 checksum;
+    u8 i;
+    u8 availableIVs[NUM_STATS];
+    u8 selectedIvs[LEGENDARY_PERFECT_IV_COUNT];
 
     ZeroBoxMonData(boxMon);
 
@@ -3286,6 +3290,52 @@ void CreateBoxMon(struct BoxPokemon *boxMon, u16 species, u8 level, u8 fixedIV,
         SetBoxMonData(boxMon, MON_DATA_SPATK_IV, &iv);
         iv = (value & (MAX_IV_MASK << 10)) >> 10;
         SetBoxMonData(boxMon, MON_DATA_SPDEF_IV, &iv);
+
+        #if P_LEGENDARY_PERFECT_IVS >= GEN_6
+            if (gBaseStats[species].flags & (FLAG_LEGENDARY | FLAG_MYTHICAL | FLAG_ULTRA_BEAST))
+            {
+                // Initialize a list of IV indices.
+                for (i = 0; i < NUM_STATS; i++)
+                {
+                    availableIVs[i] = i;
+                }
+
+                // Select the 3 IVs that will be perfected.
+                for (i = 0; i < LEGENDARY_PERFECT_IV_COUNT; i++)
+                {
+                    u8 index = Random() % (NUM_STATS - i);
+                    selectedIvs[i] = availableIVs[index];
+                    RemoveIVIndexFromList(availableIVs, index);
+                }
+                for (i = 0; i < LEGENDARY_PERFECT_IV_COUNT; i++)
+                {
+                    switch (selectedIvs[i])
+                    {
+                        case STAT_HP:
+                            SetBoxMonData(boxMon, MON_DATA_HP_IV, MAX_PER_STAT_IVS);
+                            //iv = GetBoxMonData(&daycare->mons[whichParents[i]].mon, MON_DATA_HP_IV);
+                            //SetMonData(egg, MON_DATA_HP_IV, &iv);
+                            break;
+                        case STAT_ATK:
+                            SetBoxMonData(boxMon, MON_DATA_ATK_IV, MAX_PER_STAT_IVS);
+                            break;
+                        case STAT_DEF:
+                            SetBoxMonData(boxMon, MON_DATA_DEF_IV, MAX_PER_STAT_IVS);
+                            break;
+                        case STAT_SPEED:
+                            SetBoxMonData(boxMon, MON_DATA_SPEED_IV, MAX_PER_STAT_IVS);
+                            break;
+                        case STAT_SPATK:
+                            SetBoxMonData(boxMon, MON_DATA_SPATK_IV, MAX_PER_STAT_IVS);
+                            break;
+                        case STAT_SPDEF:
+                            SetBoxMonData(boxMon, MON_DATA_SPDEF_IV, MAX_PER_STAT_IVS);
+                            break;
+                    }
+                }
+            }
+        #endif
+        
     }
 
     if (gBaseStats[species].abilities[1])
@@ -8341,3 +8391,22 @@ u16 MonTryLearningNewMoveEvolution(struct Pokemon *mon, bool8 firstMove)
     }
     return 0;
 }
+
+static void RemoveIVIndexFromList(u8 *ivs, u8 selectedIv)
+{
+    s32 i, j;
+    u8 temp[NUM_STATS];
+
+    ivs[selectedIv] = 0xFF;
+    for (i = 0; i < NUM_STATS; i++)
+    {
+        temp[i] = ivs[i];
+    }
+
+    j = 0;
+    for (i = 0; i < NUM_STATS; i++)
+    {
+        if (temp[i] != 0xFF)
+            ivs[j++] = temp[i];
+    }
+}