diff --git a/src/applications/calendar/controller/PhabricatorCalendarBrowseController.php b/src/applications/calendar/controller/PhabricatorCalendarBrowseController.php
--- a/src/applications/calendar/controller/PhabricatorCalendarBrowseController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarBrowseController.php
@@ -3,6 +3,10 @@
 final class PhabricatorCalendarBrowseController
   extends PhabricatorCalendarController {
 
+  public function shouldAllowPublic() {
+    return true;
+  }
+
   public function processRequest() {
     $now     = time();
     $request = $this->getRequest();
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventListController.php b/src/applications/calendar/controller/PhabricatorCalendarEventListController.php
--- a/src/applications/calendar/controller/PhabricatorCalendarEventListController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventListController.php
@@ -5,6 +5,10 @@
 
   private $queryKey;
 
+  public function shouldAllowPublic() {
+    return true;
+  }
+
   public function willProcessRequest(array $data) {
     $this->queryKey = idx($data, 'queryKey');
   }
diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php b/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
--- a/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventViewController.php
@@ -5,6 +5,10 @@
 
   private $id;
 
+  public function shouldAllowPublic() {
+    return true;
+  }
+
   public function willProcessRequest(array $data) {
     $this->id = $data['id'];
   }
diff --git a/src/applications/calendar/controller/PhabricatorCalendarViewController.php b/src/applications/calendar/controller/PhabricatorCalendarViewController.php
--- a/src/applications/calendar/controller/PhabricatorCalendarViewController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarViewController.php
@@ -3,6 +3,10 @@
 final class PhabricatorCalendarViewController
   extends PhabricatorCalendarController {
 
+  public function shouldAllowPublic() {
+    return true;
+  }
+
   public function processRequest() {
     $user = $this->getRequest()->getUser();
 
@@ -89,6 +93,19 @@
       $view = id(new AphrontErrorView())
         ->setSeverity(AphrontErrorView::SEVERITY_NOTICE)
         ->setTitle(pht('Successfully deleted your status.'));
+    } else if (!$request->getUser()->isLoggedIn()) {
+      $login_uri = id(new PhutilURI('/auth/start/'))
+        ->setQueryParam('next', '/calendar/');
+      $view = id(new AphrontErrorView())
+        ->setSeverity(AphrontErrorView::SEVERITY_NOTICE)
+        ->setTitle(
+          pht(
+            'You are not logged in. %s to see your calendar events.',
+            phutil_tag(
+              'a',
+              array(
+                'href' => $login_uri),
+              pht('Log in'))));
     }
 
     return $view;