diff --git a/src/battle-scene.ts b/src/battle-scene.ts
index 289c9a8f051..7352979daa0 100644
--- a/src/battle-scene.ts
+++ b/src/battle-scene.ts
@@ -866,7 +866,7 @@ export class BattleScene extends SceneBase {
     gender?: Gender,
     shiny?: boolean,
     variant?: Variant,
-    ivs?: number[],
+    ivs?: Uint8Array,
     nature?: Nature,
     dataSource?: Pokemon | PokemonData,
     postProcess?: (playerPokemon: PlayerPokemon) => void,
@@ -897,12 +897,12 @@ export class BattleScene extends SceneBase {
       if (Overrides.IVS_OVERRIDE.some(value => !isBetween(value, 0, 31))) {
         throw new Error("All IVs in the player IV override must be between 0 and 31!");
       }
-      pokemon.ivs = Overrides.IVS_OVERRIDE;
+      pokemon.ivs = new Uint8Array(Overrides.IVS_OVERRIDE);
     } else {
       if (!isBetween(Overrides.IVS_OVERRIDE, 0, 31)) {
         throw new Error("The Player IV override must be a value between 0 and 31!");
       }
-      pokemon.ivs = new Array(6).fill(Overrides.IVS_OVERRIDE);
+      pokemon.ivs = new Uint8Array(6).fill(Overrides.IVS_OVERRIDE);
     }
 
     if (Overrides.NATURE_OVERRIDE !== null) {
@@ -962,12 +962,12 @@ export class BattleScene extends SceneBase {
       if (Overrides.ENEMY_IVS_OVERRIDE.some(value => !isBetween(value, 0, 31))) {
         throw new Error("All IVs in the enemy IV override must be between 0 and 31!");
       }
-      pokemon.ivs = Overrides.ENEMY_IVS_OVERRIDE;
+      pokemon.ivs = new Uint8Array(Overrides.ENEMY_IVS_OVERRIDE);
     } else {
       if (!isBetween(Overrides.ENEMY_IVS_OVERRIDE, 0, 31)) {
         throw new Error("The Enemy IV override must be a value between 0 and 31!");
       }
-      pokemon.ivs = new Array(6).fill(Overrides.ENEMY_IVS_OVERRIDE);
+      pokemon.ivs = new Uint8Array(6).fill(Overrides.ENEMY_IVS_OVERRIDE);
     }
 
     if (Overrides.ENEMY_NATURE_OVERRIDE !== null) {
diff --git a/src/data/mystery-encounters/utils/encounter-phase-utils.ts b/src/data/mystery-encounters/utils/encounter-phase-utils.ts
index 0ba0dec896a..16d388c2e96 100644
--- a/src/data/mystery-encounters/utils/encounter-phase-utils.ts
+++ b/src/data/mystery-encounters/utils/encounter-phase-utils.ts
@@ -318,7 +318,7 @@ export async function initBattleWithEnemyConfig(partyConfig: EnemyPartyConfig):
 
       // Set IVs
       if (config.ivs) {
-        enemyPokemon.ivs = config.ivs;
+        enemyPokemon.ivs = new Uint8Array(config.ivs);
       }
 
       // Set Status
diff --git a/src/field/pokemon.ts b/src/field/pokemon.ts
index 06e5e0d85aa..a2e352ddf5d 100644
--- a/src/field/pokemon.ts
+++ b/src/field/pokemon.ts
@@ -204,7 +204,7 @@ export abstract class Pokemon extends Phaser.GameObjects.Container {
   public gender: Gender;
   public hp: number;
   public stats: number[];
-  public ivs: number[];
+  public ivs: Uint8Array;
   public nature: Nature;
   public moveset: PokemonMove[];
   /**
@@ -311,7 +311,7 @@ export abstract class Pokemon extends Phaser.GameObjects.Container {
     gender?: Gender,
     shiny?: boolean,
     variant?: Variant,
-    ivs?: number[],
+    ivs?: Uint8Array,
     nature?: Nature,
     dataSource?: Pokemon | PokemonData,
   ) {
@@ -346,7 +346,8 @@ export abstract class Pokemon extends Phaser.GameObjects.Container {
       this.id = dataSource.id;
       this.hp = dataSource.hp;
       this.stats = dataSource.stats;
-      this.ivs = dataSource.ivs;
+
+      this.ivs = new Uint8Array(dataSource.ivs);
       this.passive = !!dataSource.passive;
       if (this.variant === undefined) {
         this.variant = 0;
@@ -385,7 +386,7 @@ export abstract class Pokemon extends Phaser.GameObjects.Container {
       this.stellarTypesBoosted = dataSource.stellarTypesBoosted ?? [];
     } else {
       this.id = randSeedInt(4294967296);
-      this.ivs = ivs || getIvsFromId(this.id);
+      this.ivs = new Uint8Array(ivs || getIvsFromId(this.id));
 
       if (this.gender === undefined) {
         this.gender = this.species.generateGender();
@@ -5704,7 +5705,7 @@ export class PlayerPokemon extends Pokemon {
     gender?: Gender,
     shiny?: boolean,
     variant?: Variant,
-    ivs?: number[],
+    ivs?: Uint8Array,
     nature?: Nature,
     dataSource?: Pokemon | PokemonData,
   ) {
@@ -6324,9 +6325,9 @@ export class EnemyPokemon extends Pokemon {
 
       if (this.hasTrainer() && globalScene.currentBattle) {
         const { waveIndex } = globalScene.currentBattle;
-        const ivs: number[] = [];
-        while (ivs.length < 6) {
-          ivs.push(randSeedIntRange(Math.floor(waveIndex / 10), 31));
+        const ivs = new Uint8Array(6);
+        for (let i = 0; i < 6; i++) {
+          ivs[i] = this.randBattleSeedIntRange(Math.floor(waveIndex / 10), 31);
         }
         this.ivs = ivs;
       }
diff --git a/src/system/game-data.ts b/src/system/game-data.ts
index 3ffa7482706..5f89c0a6da8 100644
--- a/src/system/game-data.ts
+++ b/src/system/game-data.ts
@@ -1914,7 +1914,7 @@ export class GameData {
     _unlockSpeciesNature(species.speciesId);
   }
 
-  updateSpeciesDexIvs(speciesId: SpeciesId, ivs: number[]): void {
+  updateSpeciesDexIvs(speciesId: SpeciesId, ivs: Uint8Array): void {
     let dexEntry: DexEntry;
     do {
       dexEntry = globalScene.gameData.dexData[speciesId];