diff --git a/src/data/arena-tag.ts b/src/data/arena-tag.ts
index 7e895dc483f..10d4cfaad38 100644
--- a/src/data/arena-tag.ts
+++ b/src/data/arena-tag.ts
@@ -1027,6 +1027,47 @@ class FireGrassPledgeTag extends ArenaTag {
   }
 }
 
+/**
+ * Arena Tag implementing the "rainbow" effect from the combination
+ * of {@link https://bulbapedia.bulbagarden.net/wiki/Water_Pledge_(move) | Water Pledge}
+ * and {@link https://bulbapedia.bulbagarden.net/wiki/Fire_Pledge_(move) | Fire Pledge}.
+ * Doubles the secondary effect chance of moves from Pokemon on the
+ * given side of the field for 4 turns.
+ */
+class WaterFirePledgeTag extends ArenaTag {
+  constructor(sourceId: number, side: ArenaTagSide) {
+    super(ArenaTagType.WATER_FIRE_PLEDGE, 4, Moves.WATER_PLEDGE, sourceId, side);
+  }
+
+  override onAdd(arena: Arena): void {
+    // "A rainbow appeared in the sky on your/the opposing team's side!"
+    arena.scene.queueMessage(i18next.t(`arenaTag:waterFirePledgeOnAdd${this.side === ArenaTagSide.PLAYER ? "Player" : this.side === ArenaTagSide.ENEMY ? "Enemy" : ""}`));
+  }
+
+  override apply(arena: Arena, args: any[]): boolean {
+    const moveChance = args[0] as Utils.NumberHolder;
+    moveChance.value *= 2;
+    return true;
+  }
+}
+
+/**
+ * Arena Tag implementing the "swamp" effect from the combination
+ * of {@link https://bulbapedia.bulbagarden.net/wiki/Grass_Pledge_(move) | Grass Pledge}
+ * and {@link https://bulbapedia.bulbagarden.net/wiki/Water_Pledge_(move) | Water Pledge}.
+ * Quarters the Speed of Pokemon on the given side of the field for 4 turns.
+ */
+class GrassWaterPledgeTag extends ArenaTag {
+  constructor(sourceId: number, side: ArenaTagSide) {
+    super(ArenaTagType.GRASS_WATER_PLEDGE, 4, Moves.GRASS_PLEDGE, sourceId, side);
+  }
+
+  override onAdd(arena: Arena): void {
+    // "A swamp enveloped your/the opposing team!"
+    arena.scene.queueMessage(i18next.t(`arenaTag:grassWaterPledgeOnAdd${this.side === ArenaTagSide.PLAYER ? "Player" : this.side === ArenaTagSide.ENEMY ? "Enemy" : ""}`));
+  }
+}
+
 export function getArenaTag(tagType: ArenaTagType, turnCount: integer, sourceMove: Moves | undefined, sourceId: integer, targetIndex?: BattlerIndex, side: ArenaTagSide = ArenaTagSide.BOTH): ArenaTag | null {
   switch (tagType) {
   case ArenaTagType.MIST:
@@ -1078,6 +1119,10 @@ export function getArenaTag(tagType: ArenaTagType, turnCount: integer, sourceMov
     return new ImprisonTag(sourceId, side);
   case ArenaTagType.FIRE_GRASS_PLEDGE:
     return new FireGrassPledgeTag(sourceId, side);
+  case ArenaTagType.WATER_FIRE_PLEDGE:
+    return new WaterFirePledgeTag(sourceId, side);
+  case ArenaTagType.GRASS_WATER_PLEDGE:
+    return new GrassWaterPledgeTag(sourceId, side);
   default:
     return null;
   }
diff --git a/src/data/move.ts b/src/data/move.ts
index d1bfa6c2ed0..a1c54f2b6ac 100644
--- a/src/data/move.ts
+++ b/src/data/move.ts
@@ -1027,7 +1027,14 @@ export class MoveEffectAttr extends MoveAttr {
    */
   getMoveChance(user: Pokemon, target: Pokemon, move: Move, selfEffect?: Boolean, showAbility?: Boolean): integer {
     const moveChance = new Utils.NumberHolder(move.chance);
+
     applyAbAttrs(MoveEffectChanceMultiplierAbAttr, user, null, false, moveChance, move, target, selfEffect, showAbility);
+
+    if (!move.hasAttr(FlinchAttr) || moveChance.value <= move.chance) {
+      const userSide = user.isPlayer() ? ArenaTagSide.PLAYER : ArenaTagSide.ENEMY;
+      user.scene.arena.applyTagsForSide(ArenaTagType.WATER_FIRE_PLEDGE, userSide, moveChance);
+    }
+
     if (!selfEffect) {
       applyPreDefendAbAttrs(IgnoreMoveEffectsAbAttr, target, user, null, null, false, moveChance);
     }
@@ -8437,20 +8444,24 @@ export function initMoves() {
       .attr(CombinedPledgeTypeAttr)
       .attr(CombinedPledgePowerAttr)
       .attr(CombinedPledgeStabBoostAttr)
+      .attr(AddPledgeEffectAttr, ArenaTagType.WATER_FIRE_PLEDGE, Moves.FIRE_PLEDGE, true)
+      .attr(AddPledgeEffectAttr, ArenaTagType.GRASS_WATER_PLEDGE, Moves.GRASS_PLEDGE)
       .attr(BypassRedirectAttr), // technically incorrect, should only bypass Storm Drain/Lightning Rod
     new AttackMove(Moves.FIRE_PLEDGE, Type.FIRE, MoveCategory.SPECIAL, 80, 100, 10, -1, 0, 5)
       .attr(AwaitCombinedPledgeAttr)
       .attr(CombinedPledgeTypeAttr)
       .attr(CombinedPledgePowerAttr)
       .attr(CombinedPledgeStabBoostAttr)
-      .attr(AddPledgeEffectAttr, ArenaTagType.FIRE_GRASS_PLEDGE, Moves.GRASS_PLEDGE, false)
+      .attr(AddPledgeEffectAttr, ArenaTagType.FIRE_GRASS_PLEDGE, Moves.GRASS_PLEDGE)
+      .attr(AddPledgeEffectAttr, ArenaTagType.WATER_FIRE_PLEDGE, Moves.WATER_PLEDGE, true)
       .attr(BypassRedirectAttr), // technically incorrect, should only bypass Storm Drain/Lightning Rod
     new AttackMove(Moves.GRASS_PLEDGE, Type.GRASS, MoveCategory.SPECIAL, 80, 100, 10, -1, 0, 5)
       .attr(AwaitCombinedPledgeAttr)
       .attr(CombinedPledgeTypeAttr)
       .attr(CombinedPledgePowerAttr)
       .attr(CombinedPledgeStabBoostAttr)
-      .attr(AddPledgeEffectAttr, ArenaTagType.FIRE_GRASS_PLEDGE, Moves.FIRE_PLEDGE, false)
+      .attr(AddPledgeEffectAttr, ArenaTagType.GRASS_WATER_PLEDGE, Moves.WATER_PLEDGE)
+      .attr(AddPledgeEffectAttr, ArenaTagType.FIRE_GRASS_PLEDGE, Moves.FIRE_PLEDGE)
       .attr(BypassRedirectAttr), // technically incorrect, should only bypass Storm Drain/Lightning Rod
     new AttackMove(Moves.VOLT_SWITCH, Type.ELECTRIC, MoveCategory.SPECIAL, 70, 100, 20, -1, 0, 5)
       .attr(ForceSwitchOutAttr, true),
diff --git a/src/field/pokemon.ts b/src/field/pokemon.ts
index 9085d68e077..6e31f8b85aa 100644
--- a/src/field/pokemon.ts
+++ b/src/field/pokemon.ts
@@ -920,11 +920,13 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
       }
       break;
     case Stat.SPD:
-      // Check both the player and enemy to see if Tailwind should be multiplying the speed of the Pokemon
-      if    ((this.isPlayer() && this.scene.arena.getTagOnSide(ArenaTagType.TAILWIND, ArenaTagSide.PLAYER))
-          ||  (!this.isPlayer() && this.scene.arena.getTagOnSide(ArenaTagType.TAILWIND, ArenaTagSide.ENEMY))) {
+      const side = this.isPlayer() ? ArenaTagSide.PLAYER : ArenaTagSide.ENEMY;
+      if (this.scene.arena.getTagOnSide(ArenaTagType.TAILWIND, side)) {
         ret *= 2;
       }
+      if (this.scene.arena.getTagOnSide(ArenaTagType.GRASS_WATER_PLEDGE, side)) {
+        ret /= 4;
+      }
 
       if (this.getTag(BattlerTagType.SLOW_START)) {
         ret >>= 1;
diff --git a/src/locales/en/arena-tag.json b/src/locales/en/arena-tag.json
index f812ab52cbc..72097c0b3c5 100644
--- a/src/locales/en/arena-tag.json
+++ b/src/locales/en/arena-tag.json
@@ -54,7 +54,14 @@
   "safeguardOnRemove": "The field is no longer protected by Safeguard!",
   "safeguardOnRemovePlayer": "Your team is no longer protected by Safeguard!",
   "safeguardOnRemoveEnemy": "The opposing team is no longer protected by Safeguard!",
+  "fireGrassPledgeOnAdd": "A sea of fire enveloped the field!",
   "fireGrassPledgeOnAddPlayer": "A sea of fire enveloped your team!",
   "fireGrassPledgeOnAddEnemy": "A sea of fire enveloped the opposing team!",
-  "fireGrassPledgeLapse": "{{pokemonNameWithAffix}} was hurt by the sea of fire!"
+  "fireGrassPledgeLapse": "{{pokemonNameWithAffix}} was hurt by the sea of fire!",
+  "waterFirePledgeOnAdd": "A rainbow appeared in the sky!",
+  "waterFirePledgeOnAddPlayer": "A rainbow appeared in the sky on your team's side!",
+  "waterFirePledgeOnAddEnemy": "A rainbow appeared in the sky on the opposing team's side!",
+  "grassWaterPledgeOnAdd": "A swamp enveloped the field!",
+  "grassWaterPledgeOnAddPlayer": "A swamp enveloped your team!",
+  "grassWaterPledgeOnAddEnemy": "A swamp enveloped the opposing team!"
 }
\ No newline at end of file