--- a/testing/marionette/browser.js
+++ b/testing/marionette/browser.js
@@ -11,17 +11,16 @@ Cu.import("chrome://marionette/content/e
 Cu.import("chrome://marionette/content/frame.js");
 
 this.EXPORTED_SYMBOLS = ["browser"];
 
 this.browser = {};
 
 const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 
-
 /**
  * Get the <xul:browser> for the specified tab.
  *
  * @param {<xul:tab>} tab
  *     The tab whose browser needs to be returned.
  *
  * @return {<xul:browser>}
  *     The linked browser for the tab or null if no browser can be found.
@@ -141,27 +140,32 @@ browser.Context = class {
     let rv = null;
     if (this.tab) {
       rv = this.getIdForBrowser(this.contentBrowser);
     }
     return rv;
   }
 
   /**
-   * Returns the current URL of the content browser.
-   * If no browser is available, null will be returned.
+   * Returns the current URI of the content browser.
+   *
+   * @return {nsIURI}
+   *     Read-only property containing the currently loaded URL.
+   *
+   * @throws {NoSuchWindowError}
+   *     If the current ChromeWindow does not have a content browser.
    */
-  get currentURL() {
+  get currentURI() {
     // Bug 1363368 - contentBrowser could be null until we wait for its
     // initialization been finished
     if (this.contentBrowser) {
-      return this.contentBrowser.currentURI.spec;
-
+      return this.contentBrowser.currentURI;
     } else {
-      throw new NoSuchWindowError("Current window does not have a content browser");
+      throw new NoSuchWindowError(
+          "Current window does not have a content browser");
     }
   }
 
   /**
    * Retrieves the current tabmodal UI object.  According to the browser
    * associated with the currently selected tab.
    */
   getTabModalUI() {

--- a/testing/marionette/driver.js
+++ b/testing/marionette/driver.js
@@ -32,16 +32,18 @@ Cu.import("chrome://marionette/content/i
 Cu.import("chrome://marionette/content/l10n.js");
 Cu.import("chrome://marionette/content/legacyaction.js");
 Cu.import("chrome://marionette/content/logging.js");
 Cu.import("chrome://marionette/content/modal.js");
 Cu.import("chrome://marionette/content/proxy.js");
 Cu.import("chrome://marionette/content/session.js");
 Cu.import("chrome://marionette/content/wait.js");
 
+Cu.importGlobalProperties(["URL"]);
+
 this.EXPORTED_SYMBOLS = ["GeckoDriver", "Context"];
 
 var FRAME_SCRIPT = "chrome://marionette/content/listener.js";
 
 const CLICK_TO_START_PREF = "marionette.debugging.clicktostart";
 const CONTENT_LISTENER_PREF = "marionette.contentListener";
 
 const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
@@ -140,24 +142,32 @@ this.GeckoDriver = function (appName, se
 };
 
 Object.defineProperty(GeckoDriver.prototype, "a11yChecks", {
   get: function () {
     return this.capabilities.get("moz:accessibilityChecks");
   }
 });
 
+/**
+ * Returns the current URL of the ChromeWindow or content browser,
+ * depending on context.
+ *
+ * @return {URL}
+ *     Read-only property containing the currently loaded URL.
+ */
 Object.defineProperty(GeckoDriver.prototype, "currentURL", {
   get: function () {
     switch (this.context) {
       case Context.CHROME:
-        return this.getCurrentWindow().location.href;
+        let chromeWin = this.getCurrentWindow();
+        return new URL(chromeWin.location.href);
 
       case Context.CONTENT:
-        return this.curBrowser.currentURL;
+        return new URL(this.curBrowser.currentURI.spec);
     }
   }
 });
 
 Object.defineProperty(GeckoDriver.prototype, "proxy", {
   get: function () {
     return this.capabilities.get("proxy");
   }
@@ -968,17 +978,17 @@ GeckoDriver.prototype.get = function* (c
  *     Top-level browsing context has been discarded.
  * @throws {UnexpectedAlertOpenError}
  *     A modal dialog is open, blocking this operation.
  */
 GeckoDriver.prototype.getCurrentUrl = function (cmd) {
   assert.window(this.getCurrentWindow());
   assert.noUserPrompt(this.dialog);
 
-  return this.currentURL;
+  return this.currentURL.toString();
 };
 
 /**
  * Gets the current title of the window.
  *
  * @return {string}
  *     Document title of the top-level browsing context.
  *
@@ -1053,27 +1063,27 @@ GeckoDriver.prototype.goBack = function*
   assert.contentBrowser(this.curBrowser);
   assert.noUserPrompt(this.dialog);
 
   // If there is no history, just return
   if (!this.curBrowser.contentBrowser.webNavigation.canGoBack) {
     return;
   }
 
-  let currentURL = this.currentURL;
+  let lastURL = this.currentURL;
   let goBack = this.listener.goBack({pageTimeout: this.timeouts.pageLoad});
 
   // If a remoteness update interrupts our page load, this will never return
   // We need to re-issue this request to correctly poll for readyState and
   // send errors.
   this.curBrowser.pendingCommands.push(() => {
     let parameters = {
       // TODO(ato): Bug 1242595
       command_id: this.listener.activeMessageId,
-      lastSeenURL: currentURL,
+      lastSeenURL: lastURL.toString(),
       pageTimeout: this.timeouts.pageLoad,
       startTime: new Date().getTime(),
     };
     this.mm.broadcastAsyncMessage(
         "Marionette:waitForPageLoaded" + this.curBrowser.curFrameId,
         parameters);
   });
 
@@ -1096,27 +1106,27 @@ GeckoDriver.prototype.goForward = functi
   assert.contentBrowser(this.curBrowser);
   assert.noUserPrompt(this.dialog);
 
   // If there is no history, just return
   if (!this.curBrowser.contentBrowser.webNavigation.canGoForward) {
     return;
   }
 
-  let currentURL = this.currentURL;
+  let lastURL = this.currentURL;
   let goForward = this.listener.goForward({pageTimeout: this.timeouts.pageLoad});
 
   // If a remoteness update interrupts our page load, this will never return
   // We need to re-issue this request to correctly poll for readyState and
   // send errors.
   this.curBrowser.pendingCommands.push(() => {
     let parameters = {
       // TODO(ato): Bug 1242595
       command_id: this.listener.activeMessageId,
-      lastSeenURL: currentURL,
+      lastSeenURL: lastURL.toString(),
       pageTimeout: this.timeouts.pageLoad,
       startTime: new Date().getTime(),
     };
     this.mm.broadcastAsyncMessage(
         "Marionette:waitForPageLoaded" + this.curBrowser.curFrameId,
         parameters);
   });