diff --git a/lib/index.ts b/lib/index.ts
index 25d1b0d9..4de56381 100644
--- a/lib/index.ts
+++ b/lib/index.ts
@@ -12,6 +12,8 @@ import { modelsWithVision } from "./llm/LLMClient";
 require("dotenv").config({ path: ".env" });
 
 async function getBrowser(
+  apiKey: string | undefined,
+  projectId: string | undefined,
   env: "LOCAL" | "BROWSERBASE" = "LOCAL",
   headless: boolean = false,
   logger: (message: {
@@ -20,55 +22,103 @@ async function getBrowser(
     level?: 0 | 1 | 2;
   }) => void,
   browserbaseSessionCreateParams?: Browserbase.Sessions.SessionCreateParams,
+  browserbaseResumeSessionID?: string,
 ) {
-  if (env === "BROWSERBASE" && !process.env.BROWSERBASE_API_KEY) {
-    logger({
-      category: "Init",
-      message:
-        "BROWSERBASE_API_KEY is required to use BROWSERBASE env. Defaulting to LOCAL.",
-      level: 0,
-    });
-    env = "LOCAL";
-  }
-
-  if (env === "BROWSERBASE" && !process.env.BROWSERBASE_PROJECT_ID) {
-    logger({
-      category: "Init",
-      message:
-        "BROWSERBASE_PROJECT_ID is required to use BROWSERBASE env. Defaulting to LOCAL.",
-      level: 0,
-    });
-    env = "LOCAL";
+  if (env === "BROWSERBASE") {
+    if (!apiKey) {
+      logger({
+        category: "Init",
+        message:
+          "BROWSERBASE_API_KEY is required to use BROWSERBASE env. Defaulting to LOCAL.",
+        level: 0,
+      });
+      env = "LOCAL";
+    }
+    if (!projectId) {
+      logger({
+        category: "Init",
+        message:
+          "BROWSERBASE_PROJECT_ID is required for some Browserbase features that may not work without it.",
+        level: 1,
+      });
+    }
   }
 
   if (env === "BROWSERBASE") {
+    if (!apiKey) {
+      throw new Error("BROWSERBASE_API_KEY is required.");
+    }
+
     let debugUrl: string | undefined = undefined;
     let sessionUrl: string | undefined = undefined;
+    let sessionId: string;
+    let connectUrl: string;
 
-    logger({
-      category: "Init",
-      message: "Connecting you to Browserbase...",
-      level: 0,
-    });
     const browserbase = new Browserbase({
-      apiKey: process.env.BROWSERBASE_API_KEY,
-    });
-    const session = await browserbase.sessions.create({
-      projectId: process.env.BROWSERBASE_PROJECT_ID,
-      ...browserbaseSessionCreateParams,
+      apiKey,
     });
 
-    const sessionId = session.id;
-    const connectUrl = session.connectUrl;
-    const browser = await chromium.connectOverCDP(connectUrl);
+    if (browserbaseResumeSessionID) {
+      // Validate the session status
+      try {
+        const sessionStatus = await browserbase.sessions.retrieve(
+          browserbaseResumeSessionID,
+        );
+
+        if (sessionStatus.status !== "RUNNING") {
+          throw new Error(
+            `Session ${browserbaseResumeSessionID} is not running (status: ${sessionStatus.status})`,
+          );
+        }
+
+        sessionId = browserbaseResumeSessionID;
+        connectUrl = `wss://connect.browserbase.com?apiKey=${apiKey}&sessionId=${sessionId}`;
+
+        logger({
+          category: "Init",
+          message: "Resuming existing Browserbase session...",
+          level: 0,
+        });
+      } catch (error) {
+        logger({
+          category: "Init",
+          message: `Failed to resume session ${browserbaseResumeSessionID}: ${error.message}`,
+          level: 0,
+        });
+        throw error;
+      }
+    } else {
+      // Create new session (existing code)
+      logger({
+        category: "Init",
+        message: "Creating new Browserbase session...",
+        level: 0,
+      });
+
+      if (!projectId) {
+        throw new Error(
+          "BROWSERBASE_PROJECT_ID is required for new Browserbase sessions.",
+        );
+      }
 
+      const session = await browserbase.sessions.create({
+        projectId,
+        ...browserbaseSessionCreateParams,
+      });
+
+      sessionId = session.id;
+      connectUrl = session.connectUrl;
+    }
+
+    const browser = await chromium.connectOverCDP(connectUrl);
     const { debuggerUrl } = await browserbase.sessions.debug(sessionId);
 
     debugUrl = debuggerUrl;
     sessionUrl = `https://www.browserbase.com/sessions/${sessionId}`;
+
     logger({
       category: "Init",
-      message: `Browserbase session started.\n\nSession Url: ${sessionUrl}\n\nLive debug accessible here: ${debugUrl}.`,
+      message: `Browserbase session ${browserbaseResumeSessionID ? "resumed" : "started"}.\n\nSession Url: ${sessionUrl}\n\nLive debug accessible here: ${debugUrl}.`,
       level: 0,
     });
 
@@ -182,6 +232,8 @@ export class Stagehand {
   public page: Page;
   public context: BrowserContext;
   private env: "LOCAL" | "BROWSERBASE";
+  private apiKey: string | undefined;
+  private projectId: string | undefined;
   private verbose: 0 | 1 | 2;
   private debugDom: boolean;
   private defaultModelName: AvailableModel;
@@ -194,10 +246,13 @@ export class Stagehand {
   private domSettleTimeoutMs: number;
   private browserBaseSessionCreateParams?: Browserbase.Sessions.SessionCreateParams;
   private enableCaching: boolean;
+  private browserbaseResumeSessionID?: string;
 
   constructor(
     {
       env,
+      apiKey,
+      projectId,
       verbose,
       debugDom,
       llmProvider,
@@ -206,8 +261,11 @@ export class Stagehand {
       browserBaseSessionCreateParams,
       domSettleTimeoutMs,
       enableCaching,
+      browserbaseResumeSessionID,
     }: {
       env: "LOCAL" | "BROWSERBASE";
+      apiKey?: string;
+      projectId?: string;
       verbose?: 0 | 1 | 2;
       debugDom?: boolean;
       llmProvider?: LLMProvider;
@@ -220,6 +278,7 @@ export class Stagehand {
       domSettleTimeoutMs?: number;
       browserBaseSessionCreateParams?: Browserbase.Sessions.SessionCreateParams;
       enableCaching?: boolean;
+      browserbaseResumeSessionID?: string;
     } = {
       env: "BROWSERBASE",
     },
@@ -231,6 +290,8 @@ export class Stagehand {
       llmProvider || new LLMProvider(this.logger, this.enableCaching);
     this.env = env;
     this.observations = {};
+    this.apiKey = apiKey;
+    this.projectId = projectId;
     this.actions = {};
     this.verbose = verbose ?? 0;
     this.debugDom = debugDom ?? false;
@@ -238,6 +299,7 @@ export class Stagehand {
     this.domSettleTimeoutMs = domSettleTimeoutMs ?? 60_000;
     this.headless = headless ?? false;
     this.browserBaseSessionCreateParams = browserBaseSessionCreateParams;
+    this.browserbaseResumeSessionID = browserbaseResumeSessionID;
   }
 
   async init({
@@ -247,10 +309,13 @@ export class Stagehand {
     sessionUrl: string;
   }> {
     const { context, debugUrl, sessionUrl } = await getBrowser(
+      this.apiKey,
+      this.projectId,
       this.env,
       this.headless,
       this.logger,
       this.browserBaseSessionCreateParams,
+      this.browserbaseResumeSessionID,
     ).catch((e) => {
       console.error("Error in init:", e);
       return { context: undefined, debugUrl: undefined, sessionUrl: undefined };
diff --git a/package-lock.json b/package-lock.json
index d3a4b7cb..f3cd9d11 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -126,6 +126,7 @@
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/@browserbasehq/sdk/-/sdk-2.0.0.tgz",
       "integrity": "sha512-BdPlZyn0dpXlL70gNK4acpqWIRB+edo2z0/GalQdWghRq8iQjySd9fVIF3evKH1p2wCYekZJRK6tm29YfXB67g==",
+      "license": "Apache-2.0",
       "dependencies": {
         "@types/node": "^18.11.18",
         "@types/node-fetch": "^2.6.4",