diff --git a/.changeset/social-moles-wish.md b/.changeset/social-moles-wish.md
new file mode 100644
index 000000000..017cc4bf5
--- /dev/null
+++ b/.changeset/social-moles-wish.md
@@ -0,0 +1,5 @@
+---
+"@browserbasehq/stagehand": patch
+---
+
+remove need for duplicate project id if already passed to Stagehand
diff --git a/lib/index.ts b/lib/index.ts
index 51c835c86..3b5e5142b 100644
--- a/lib/index.ts
+++ b/lib/index.ts
@@ -73,7 +73,7 @@ async function getBrowser(
   env: "LOCAL" | "BROWSERBASE" = "LOCAL",
   headless: boolean = false,
   logger: (message: LogLine) => void,
-  browserbaseSessionCreateParams?: Browserbase.Sessions.SessionCreateParams,
+  browserbaseSessionCreateParams?: ConstructorParams["browserbaseSessionCreateParams"],
   browserbaseSessionID?: string,
   localBrowserLaunchOptions?: LocalBrowserLaunchOptions,
 ): Promise<BrowserResult> {
@@ -166,6 +166,7 @@ async function getBrowser(
           stagehand: "true",
         },
       });
+      // Final projectId used: browserbaseSessionCreateParams.projectId || projectId
 
       sessionId = session.id;
       connectUrl = session.connectUrl;
@@ -377,7 +378,7 @@ export class Stagehand {
   protected apiKey: string | undefined;
   private projectId: string | undefined;
   private externalLogger?: (logLine: LogLine) => void;
-  private browserbaseSessionCreateParams?: Browserbase.Sessions.SessionCreateParams;
+  private browserbaseSessionCreateParams?: ConstructorParams["browserbaseSessionCreateParams"];
   public variables: { [key: string]: unknown };
   private contextPath?: string;
   public llmClient: LLMClient;
diff --git a/types/api.ts b/types/api.ts
index 0b1345560..07e955c6c 100644
--- a/types/api.ts
+++ b/types/api.ts
@@ -20,7 +20,10 @@ export interface StartSessionParams {
   verbose: number;
   debugDom: boolean;
   systemPrompt?: string;
-  browserbaseSessionCreateParams?: Browserbase.Sessions.SessionCreateParams;
+  browserbaseSessionCreateParams?: Omit<
+    Browserbase.Sessions.SessionCreateParams,
+    "projectId"
+  > & { projectId?: string };
   selfHeal?: boolean;
   waitForCaptchaSolves?: boolean;
   actionTimeoutMs?: number;
diff --git a/types/stagehand.ts b/types/stagehand.ts
index 667cce86d..940e90ee2 100644
--- a/types/stagehand.ts
+++ b/types/stagehand.ts
@@ -46,8 +46,12 @@ export interface ConstructorParams {
   /**
    * The parameters to use for creating a Browserbase session
    * See https://docs.browserbase.com/reference/api/create-a-session
+   * Note: projectId is optional here as it will use the main projectId parameter if not provided
    */
-  browserbaseSessionCreateParams?: Browserbase.Sessions.SessionCreateParams;
+  browserbaseSessionCreateParams?: Omit<
+    Browserbase.Sessions.SessionCreateParams,
+    "projectId"
+  > & { projectId?: string };
   /**
    * Enable caching of LLM responses
    * @default true