diff --git a/apps/client/src/scenes/game/application/network/PlayerMoveSender.ts b/apps/client/src/scenes/game/application/network/PlayerMoveSender.ts
index 9efa0c6..df0c394 100644
--- a/apps/client/src/scenes/game/application/network/PlayerMoveSender.ts
+++ b/apps/client/src/scenes/game/application/network/PlayerMoveSender.ts
@@ -3,6 +3,7 @@
  * ローカルプレイヤー移動の送信責務を提供する
  * シミュレーション層から通信実装を分離する
  */
+import { config } from "@client/config";
 import { socketManager } from "@client/network/SocketManager";
 
 /** 移動送信のインターフェース型 */
@@ -10,10 +11,45 @@
   sendMove: (x: number, y: number) => void;
 };
 
+type QuantizedPosition = {
+  x: number;
+  y: number;
+};
+
 /** ソケット経由で移動送信を行う実装 */
 export class SocketPlayerMoveSender implements MoveSender {
+  private lastSentPosition: QuantizedPosition | null = null;
+
   /** 指定座標をサーバーへ送信する */
   public sendMove(x: number, y: number): void {
-    socketManager.game.sendMove(x, y);
+    const quantizedPosition = this.quantizePosition(x, y);
+    const lastPosition = this.lastSentPosition;
+
+    if (
+      lastPosition
+      && lastPosition.x === quantizedPosition.x
+      && lastPosition.y === quantizedPosition.y
+    ) {
+      return;
+    }
+
+    this.lastSentPosition = quantizedPosition;
+    socketManager.game.sendMove(quantizedPosition.x, quantizedPosition.y);
+  }
+
+  private quantizePosition(x: number, y: number): QuantizedPosition {
+    return {
+      x: this.quantizeAxis(x),
+      y: this.quantizeAxis(y),
+    };
+  }
+
+  private quantizeAxis(value: number): number {
+    if (!Number.isFinite(value)) {
+      return 0;
+    }
+
+    const scale = config.GAME_CONFIG.POSITION_QUANTIZE_SCALE;
+    return Math.round(value * scale) / scale;
   }
 }
\ No newline at end of file
diff --git a/apps/server/src/domains/game/application/useCases/startGameUseCase.ts b/apps/server/src/domains/game/application/useCases/startGameUseCase.ts
index 0163655..ed6fa07 100644
--- a/apps/server/src/domains/game/application/useCases/startGameUseCase.ts
+++ b/apps/server/src/domains/game/application/useCases/startGameUseCase.ts
@@ -58,7 +58,9 @@
         output.publishMapCellUpdatesToRoom(roomId, tickData.cellUpdates);
       }
 
-      output.publishUpdateHurricanesToRoom(roomId, tickData.hurricaneUpdates);
+      if (tickData.hurricaneUpdates.length > 0) {
+        output.publishUpdateHurricanesToRoom(roomId, tickData.hurricaneUpdates);
+      }
     },
     onGameEnd: (resultPayload) => {
       logEvent(logScopes.GAME_USE_CASE, {
diff --git a/apps/server/src/network/adapters/socketEmitters.ts b/apps/server/src/network/adapters/socketEmitters.ts
index dfe1fc3..4fb57bb 100644
--- a/apps/server/src/network/adapters/socketEmitters.ts
+++ b/apps/server/src/network/adapters/socketEmitters.ts
@@ -15,6 +15,11 @@
   <TEvent extends SocketEventName>(roomId: string, event: TEvent, payload: ServerToClientPayloadOf<TEvent>): void;
 };
 
+type EmitToRoomVolatile = {
+  <TEvent extends SocketEventName>(roomId: string, event: TEvent): void;
+  <TEvent extends SocketEventName>(roomId: string, event: TEvent, payload: ServerToClientPayloadOf<TEvent>): void;
+};
+
 type EmitToRoomExceptSocket = {
   <TEvent extends SocketEventName>(roomId: string, excludedSocketId: string, event: TEvent): void;
   <TEvent extends SocketEventName>(roomId: string, excludedSocketId: string, event: TEvent, payload: ServerToClientPayloadOf<TEvent>): void;
@@ -56,6 +61,17 @@
   };
 };
 
+/** ルーム単位の volatile 送信関数を生成する */
+export const createEmitToRoomVolatile = (io: Server): EmitToRoomVolatile => {
+  return (roomId: string, event: SocketEventName, payload?: unknown) => {
+    emitWithOptionalPayload(
+      (eventName, body) => io.to(roomId).volatile.emit(eventName, body),
+      event,
+      payload,
+    );
+  };
+};
+
 /** ルーム送信時に特定ソケットを除外する送信関数を生成する */
 export const createEmitToRoomExceptSocket = (io: Server): EmitToRoomExceptSocket => {
   return (roomId: string, excludedSocketId: string, event: SocketEventName, payload?: unknown) => {
diff --git a/apps/server/src/network/handlers/CommonHandler.ts b/apps/server/src/network/handlers/CommonHandler.ts
index 6348c9d..493e951 100644
--- a/apps/server/src/network/handlers/CommonHandler.ts
+++ b/apps/server/src/network/handlers/CommonHandler.ts
@@ -6,6 +6,7 @@
 import {
   createEmitToAll,
   createEmitToRoom,
+  createEmitToRoomVolatile,
   createEmitToRoomExceptSocket,
   createEmitToSocket,
   createEmitToSocketById,
@@ -15,6 +16,7 @@
 export type CommonHandlerContext = {
   emitToAll: ReturnType<typeof createEmitToAll>;
   emitToRoom: ReturnType<typeof createEmitToRoom>;
+  emitToRoomVolatile: ReturnType<typeof createEmitToRoomVolatile>;
   emitToRoomExceptSocket: ReturnType<typeof createEmitToRoomExceptSocket>;
   emitToSocket: ReturnType<typeof createEmitToSocket>;
   emitToSocketById: ReturnType<typeof createEmitToSocketById>;
@@ -28,6 +30,7 @@
   return {
     emitToAll: createEmitToAll(io),
     emitToRoom: createEmitToRoom(io),
+    emitToRoomVolatile: createEmitToRoomVolatile(io),
     emitToRoomExceptSocket: createEmitToRoomExceptSocket(io),
     emitToSocket: createEmitToSocket(socket),
     emitToSocketById: createEmitToSocketById(io),
diff --git a/apps/server/src/network/handlers/game/createGameOutputAdapter.ts b/apps/server/src/network/handlers/game/createGameOutputAdapter.ts
index e0ee30f..0fb931b 100644
--- a/apps/server/src/network/handlers/game/createGameOutputAdapter.ts
+++ b/apps/server/src/network/handlers/game/createGameOutputAdapter.ts
@@ -57,7 +57,7 @@
       players: UpdatePlayersPayload,
     ) => {
       const sanitizedPlayers = sanitizeUpdatePlayersPayload(players);
-      common.emitToRoom(
+      common.emitToRoomVolatile(
         roomId,
         protocol.SocketEvents.UPDATE_PLAYERS,
         sanitizedPlayers,
@@ -78,7 +78,7 @@
       roomId: RoomId,
       hurricanes: UpdateHurricanesPayload,
     ) => {
-      common.emitToRoom(
+      common.emitToRoomVolatile(
         roomId,
         protocol.SocketEvents.UPDATE_HURRICANES,
         hurricanes,
diff --git a/packages/shared/src/config/gameConfig.ts b/packages/shared/src/config/gameConfig.ts
index 6226512..aaa29d8 100644
--- a/packages/shared/src/config/gameConfig.ts
+++ b/packages/shared/src/config/gameConfig.ts
@@ -11,6 +11,7 @@
 
   // ネットワーク同期設定（クライアント/サーバー契約）
   PLAYER_POSITION_UPDATE_MS: 50, // 座標送信間隔（20Hz）
+  POSITION_QUANTIZE_SCALE: 100, // 送信座標の量子化スケール（100なら小数第2位まで保持）
 
   // グリッド（マス）設定（クライアント/サーバー契約）
   GRID_COLS: 40, // 横のマス数（グリッド単位）