diff --git a/src/core/BinaryCodec.ts b/src/core/BinaryCodec.ts
index b4fa6337a..780789328 100644
--- a/src/core/BinaryCodec.ts
+++ b/src/core/BinaryCodec.ts
@@ -9,6 +9,7 @@ import {
   INTENT_FLAG_OPTION_A,
   INTENT_FLAG_OPTION_B,
   createBinaryProtocolContext,
+  hasBinaryIntentOpcode,
   intentTypeToOpcode,
   opcodeToIntentType,
   opcodeToUnitType,
@@ -554,6 +555,8 @@ function encodeIntent(
       writer.writeBoolean(intent.paused);
       return;
     case "kick_player":
+      writeRequiredPlayerRef(writer, intent.target, context);
+      return;
     case "update_game_config":
       throw new Error(`Unsupported binary intent type: ${intent.type}`);
   }
@@ -750,6 +753,12 @@ function decodeIntent(
         type: "toggle_pause",
         paused: reader.readBoolean(),
       };
+    case "kick_player":
+      assertIntentFlags(intentType, flags, 0);
+      return {
+        type: "kick_player",
+        target: readRequiredPlayerRef(reader, context),
+      };
   }
 
   throw new Error(`Unhandled binary intent type: ${intentType}`);
@@ -824,7 +833,7 @@ export function isBinaryGameplayClientMessage(
   message: ClientMessage,
 ): message is BinaryClientGameplayMessage {
   return (
-    message.type === "intent" ||
+    (message.type === "intent" && hasBinaryIntentOpcode(message.intent.type)) ||
     message.type === "hash" ||
     message.type === "ping"
   );
diff --git a/src/core/BinaryProtocol.ts b/src/core/BinaryProtocol.ts
index deff69cee..71b8727da 100644
--- a/src/core/BinaryProtocol.ts
+++ b/src/core/BinaryProtocol.ts
@@ -49,6 +49,7 @@ export enum BinaryIntentType {
   AllianceExtension = 20,
   DeleteUnit = 21,
   TogglePause = 22,
+  KickPlayer = 23,
 }
 
 export const INTENT_FLAG_OPTION_A = 1 << 0;
@@ -88,7 +89,7 @@ const INTENT_TYPE_TO_OPCODE: Record<
   quick_chat: BinaryIntentType.QuickChat,
   allianceExtension: BinaryIntentType.AllianceExtension,
   delete_unit: BinaryIntentType.DeleteUnit,
-  kick_player: undefined,
+  kick_player: BinaryIntentType.KickPlayer,
   toggle_pause: BinaryIntentType.TogglePause,
   update_game_config: undefined,
 };
@@ -116,6 +117,7 @@ const OPCODE_TO_INTENT_TYPE: Record<BinaryIntentType, Intent["type"]> = {
   [BinaryIntentType.AllianceExtension]: "allianceExtension",
   [BinaryIntentType.DeleteUnit]: "delete_unit",
   [BinaryIntentType.TogglePause]: "toggle_pause",
+  [BinaryIntentType.KickPlayer]: "kick_player",
 };
 
 const UNIT_TYPE_TO_OPCODE = new Map<UnitType, number>(
@@ -155,6 +157,10 @@ export function intentTypeToOpcode(
   return opcode;
 }
 
+export function hasBinaryIntentOpcode(intentType: Intent["type"]): boolean {
+  return INTENT_TYPE_TO_OPCODE[intentType] !== undefined;
+}
+
 export function opcodeToIntentType(opcode: number): Intent["type"] {
   const intentType = OPCODE_TO_INTENT_TYPE[opcode as BinaryIntentType];
   if (intentType === undefined) {
diff --git a/tests/core/BinaryCodec.test.ts b/tests/core/BinaryCodec.test.ts
index fb5c55e0e..630c6dcbb 100644
--- a/tests/core/BinaryCodec.test.ts
+++ b/tests/core/BinaryCodec.test.ts
@@ -5,6 +5,7 @@ import {
   decodeBinaryServerGameplayMessage,
   encodeBinaryClientGameplayMessage,
   encodeBinaryServerGameplayMessage,
+  isBinaryGameplayClientMessage,
 } from "../../src/core/BinaryCodec";
 import { BINARY_PROTOCOL_VERSION } from "../../src/core/BinaryProtocol";
 import {
@@ -251,6 +252,13 @@ const clientIntentMessages: ClientIntentMessage[] = [
       paused: true,
     },
   },
+  {
+    type: "intent",
+    intent: {
+      type: "kick_player",
+      target: "P0000002",
+    },
+  },
 ];
 
 describe("BinaryCodec", () => {
@@ -283,6 +291,28 @@ describe("BinaryCodec", () => {
     expect(decoded).toEqual(message);
   });
 
+  it("only classifies supported intents as binary gameplay messages", () => {
+    expect(
+      isBinaryGameplayClientMessage({
+        type: "intent",
+        intent: {
+          type: "kick_player",
+          target: "P0000002",
+        },
+      } as ClientIntentMessage),
+    ).toBe(true);
+
+    expect(
+      isBinaryGameplayClientMessage({
+        type: "intent",
+        intent: {
+          type: "update_game_config",
+          config: {},
+        },
+      } as ClientIntentMessage),
+    ).toBe(false);
+  });
+
   it("round-trips server turn messages", () => {
     const message: ServerTurnMessage = {
       type: "turn",
diff --git a/tests/server/GameServerBinaryProtocol.test.ts b/tests/server/GameServerBinaryProtocol.test.ts
index 4f34b6e1b..5aace70a0 100644
--- a/tests/server/GameServerBinaryProtocol.test.ts
+++ b/tests/server/GameServerBinaryProtocol.test.ts
@@ -237,6 +237,65 @@ describe("GameServer binary gameplay protocol", () => {
     );
   });
 
+  it("supports host kicks via binary gameplay intents after start", () => {
+    const logger = createMockLogger();
+    const hostPersistentId = "66666666-6666-4666-8666-666666666666";
+    const game = new GameServer(
+      "TEST0005",
+      logger as any,
+      Date.now(),
+      {
+        turnIntervalMs: () => 100,
+        env: () => 0,
+      } as any,
+      createGameConfig(),
+      hostPersistentId,
+    );
+
+    const host = createClient("P0000001", hostPersistentId, "Host");
+    const target = createClient(
+      "P0000002",
+      "77777777-7777-4777-8777-777777777777",
+      "Target",
+    );
+
+    expect(game.joinClient(host.client)).toBe("joined");
+    expect(game.joinClient(target.client)).toBe("joined");
+    game.start();
+
+    const startPayload = host.ws.sent.find(
+      (message): message is string =>
+        typeof message === "string" && message.includes('"type":"start"'),
+    );
+    expect(startPayload).toBeDefined();
+
+    const binaryContext = binaryContextFromGameStartInfo(
+      JSON.parse(startPayload!).gameStartInfo,
+    );
+    const kickMessage = encodeBinaryClientGameplayMessage(
+      {
+        type: "intent",
+        intent: {
+          type: "kick_player",
+          target: "P0000002",
+        },
+      },
+      binaryContext,
+    );
+
+    host.ws.emit("message", kickMessage, true);
+
+    expect(target.ws.sent).toEqual(
+      expect.arrayContaining([
+        expect.stringContaining('"error":"kick_reason.lobby_creator"'),
+      ]),
+    );
+    expect(target.ws.readyState).toBe(3);
+    expect(game.activeClients.map((client) => client.clientID)).toEqual([
+      "P0000001",
+    ]);
+  });
+
   it("kicks malformed binary gameplay messages after start", () => {
     const logger = createMockLogger();
     const game = new GameServer(