diff --git a/webapi/Controllers/ChatHistoryController.cs b/webapi/Controllers/ChatHistoryController.cs
index 1292ca207..64e77e322 100644
--- a/webapi/Controllers/ChatHistoryController.cs
+++ b/webapi/Controllers/ChatHistoryController.cs
@@ -139,6 +139,7 @@ public async Task<IActionResult> GetChatSessionByIdAsync(Guid chatId)
     [ProducesResponseType(StatusCodes.Status404NotFound)]
     public async Task<IActionResult> GetAllChatSessionsAsync(string userId)
     {
+        // TODO: [Issue #141] Remove this once we remove userId from route
         if (!userId.Equals(this._authInfo.UserId, StringComparison.Ordinal))
         {
             return this.Forbid("User id does not match request.");
diff --git a/webapi/Controllers/ChatParticipantController.cs b/webapi/Controllers/ChatParticipantController.cs
index d20cba736..661bde5df 100644
--- a/webapi/Controllers/ChatParticipantController.cs
+++ b/webapi/Controllers/ChatParticipantController.cs
@@ -56,31 +56,31 @@ public ChatParticipantController(
     [ProducesResponseType(StatusCodes.Status200OK)]
     [ProducesResponseType(StatusCodes.Status400BadRequest)]
     public async Task<IActionResult> JoinChatAsync(
-        Guid chatId,
         [FromServices] IHubContext<MessageRelayHub> messageRelayHubContext,
-        [FromServices] IAuthInfo authInfo)
+        [FromServices] IAuthInfo authInfo,
+        [FromBody] ChatParticipant chatParticipantParam)
     {
-        var chatIdString = chatId.ToString();
-        var userId = authInfo.UserId;
+        string chatId = chatParticipantParam.ChatId;
+        string userId = authInfo.UserId;
 
         // Make sure the chat session exists.
-        if (!await this._chatSessionRepository.TryFindByIdAsync(chatIdString, v => _ = v))
+        if (!await this._chatSessionRepository.TryFindByIdAsync(chatId, v => _ = v))
         {
             return this.BadRequest("Chat session does not exist.");
         }
 
         // Make sure the user is not already in the chat session.
-        if (await this._chatParticipantRepository.IsUserInChatAsync(userId, chatIdString))
+        if (await this._chatParticipantRepository.IsUserInChatAsync(userId, chatId))
         {
             return this.BadRequest("User is already in the chat session.");
         }
 
-        var chatParticipant = new ChatParticipant(userId, chatIdString);
+        var chatParticipant = new ChatParticipant(userId, chatId);
         await this._chatParticipantRepository.CreateAsync(chatParticipant);
 
         // Broadcast the user joined event to all the connected clients.
         // Note that the client who initiated the request may not have joined the group.
-        await messageRelayHubContext.Clients.Group(chatIdString).SendAsync(UserJoinedClientCall, chatIdString, userId);
+        await messageRelayHubContext.Clients.Group(chatId).SendAsync(UserJoinedClientCall, chatId, userId);
 
         return this.Ok(chatParticipant);
     }
diff --git a/webapp/src/libs/hooks/useChat.ts b/webapp/src/libs/hooks/useChat.ts
index 8f4c13d0c..23559a785 100644
--- a/webapp/src/libs/hooks/useChat.ts
+++ b/webapp/src/libs/hooks/useChat.ts
@@ -277,7 +277,7 @@ export const useChat = () => {
     const joinChat = async (chatId: string) => {
         const accessToken = await AuthHelper.getSKaaSAccessToken(instance, inProgress);
         try {
-            await chatService.joinChatAsync(chatId, accessToken).then(async (result: IChatSession) => {
+            await chatService.joinChatAsync(userId, chatId, accessToken).then(async (result: IChatSession) => {
                 // Get chat messages
                 const chatMessages = await chatService.getChatMessagesAsync(result.id, 0, 100, accessToken);