diff --git a/calendar/lib.php b/calendar/lib.php
index da878b80b4a..11abe2eeac1 100644
--- a/calendar/lib.php
+++ b/calendar/lib.php
@@ -3722,23 +3722,8 @@ function calendar_get_allowed_event_types(int $courseid = null) {
 
     if (!empty($courseid) && $courseid != SITEID) {
         $context = \context_course::instance($courseid);
-        $groups = groups_get_all_groups($courseid);
-
         $types['user'] = has_capability('moodle/calendar:manageownentries', $context);
-
-        if (has_capability('moodle/calendar:manageentries', $context)) {
-            $types['course'] = true;
-
-            $types['group'] = (!empty($groups) && has_capability('moodle/site:accessallgroups', $context))
-                || array_filter($groups, function($group) use ($USER) {
-                    return groups_is_member($group->id);
-                });
-        } else if (has_capability('moodle/calendar:managegroupentries', $context)) {
-            $types['group'] = (!empty($groups) && has_capability('moodle/site:accessallgroups', $context))
-                || array_filter($groups, function($group) use ($USER) {
-                    return groups_is_member($group->id);
-                });
-        }
+        calendar_internal_update_course_and_group_permission($courseid, $context, $types);
     }
 
     if (has_capability('moodle/calendar:manageentries', \context_course::instance(SITEID))) {
@@ -3823,23 +3808,7 @@ function calendar_get_allowed_event_types(int $courseid = null) {
                 context_helper::preload_from_record($coursewithgroup);
                 $context = context_course::instance($coursewithgroup->id);
 
-                if (has_capability('moodle/calendar:manageentries', $context)) {
-                    // The user has access to manage calendar entries for the whole course.
-                    // This includes groups if they have the accessallgroups capability.
-                    $types['course'] = true;
-                    if (has_capability('moodle/site:accessallgroups', $context)) {
-                        // The user also has access to all groups so they can add calendar entries to any group.
-                        // The manageentries capability overrides the managegroupentries capability.
-                        $types['group'] = true;
-                        break;
-                    }
-
-                    if (empty($types['group']) && has_capability('moodle/calendar:managegroupentries', $context)) {
-                        // The user has the managegroupentries capability.
-                        // If they have access to _any_ group, then they can create calendar entries within that group.
-                        $types['group'] = !empty(groups_get_all_groups($coursewithgroup->id, $USER->id));
-                    }
-                }
+                calendar_internal_update_course_and_group_permission($coursewithgroup->id, $context, $types);
 
                 // Okay, course and group event types are allowed, no need to keep the loop iteration.
                 if ($types['course'] == true && $types['group'] == true) {
@@ -3873,3 +3842,43 @@ function calendar_get_allowed_event_types(int $courseid = null) {
 
     return $types;
 }
+
+/**
+ * Given a course id, and context, updates the permission types array to add the 'course' or 'group'
+ * permission if it is relevant for that course.
+ *
+ * For efficiency, if they already have 'course' or 'group' then it skips checks.
+ *
+ * Do not call this function directly, it is only for use by calendar_get_allowed_event_types().
+ *
+ * @param int $courseid Course id
+ * @param context $context Context for that course
+ * @param array $types Current permissions
+ */
+function calendar_internal_update_course_and_group_permission(int $courseid, context $context, array &$types) {
+    if (!$types['course']) {
+        // If they have manageentries permission on the course, then they can update this course. 
+        if (has_capability('moodle/calendar:manageentries', $context)) {
+            $types['course'] = true;
+        }
+    }
+    // To update group events they must have EITHER manageentries OR managegroupentries.
+    if (!$types['group'] && (has_capability('moodle/calendar:manageentries', $context) ||
+            has_capability('moodle/calendar:managegroupentries', $context))) {
+        // And they also need for a group to exist on the course.
+        $groups = groups_get_all_groups($courseid);
+        if (!empty($groups)) {
+            // And either accessallgroups, or belong to one of the groups.
+            if (has_capability('moodle/site:accessallgroups', $context)) {
+                $types['group'] = true;
+            } else {
+                foreach ($groups as $group) {
+                    if (groups_is_member($group->id)) {
+                        $types['group'] = true;
+                        break;
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/calendar/tests/lib_test.php b/calendar/tests/lib_test.php
index 5264d9da7a8..96af6075ba8 100644
--- a/calendar/tests/lib_test.php
+++ b/calendar/tests/lib_test.php
@@ -546,6 +546,10 @@ class core_calendar_lib_testcase extends advanced_testcase {
 
         $this->setUser($user);
 
+        // In general for all courses, they don't have the ability to add course events yet.
+        $types = calendar_get_allowed_event_types();
+        $this->assertFalse($types['course']);
+
         assign_capability('moodle/calendar:manageentries', CAP_ALLOW, $roleid, $context1, true);
         assign_capability('moodle/calendar:manageentries', CAP_PROHIBIT, $roleid, $context2, true);
 
@@ -554,12 +558,20 @@ class core_calendar_lib_testcase extends advanced_testcase {
         $types = calendar_get_allowed_event_types($course1->id);
         $this->assertTrue($types['course']);
 
+        // If calling function without specified course,  there is still a course where they have it.
+        $types = calendar_get_allowed_event_types();
+        $this->assertTrue($types['course']);
+
         assign_capability('moodle/calendar:manageentries', CAP_PROHIBIT, $roleid, $context1, true);
 
         // The user only now has the correct capability in both course 1 and 2 so we
         // expect both to be in the results.
         $types = calendar_get_allowed_event_types($course3->id);
         $this->assertFalse($types['course']);
+
+        // They now do not have permission in any course.
+        $types = calendar_get_allowed_event_types();
+        $this->assertFalse($types['course']);
     }
 
     public function test_calendar_get_allowed_event_types_group_no_acces_to_diff_groups() {
@@ -582,6 +594,11 @@ class core_calendar_lib_testcase extends advanced_testcase {
         $types = calendar_get_allowed_event_types($course->id);
         $this->assertTrue($types['course']);
         $this->assertFalse($types['group']);
+
+        // Same result applies when not providing a specific course as they are only on one course.
+        $types = calendar_get_allowed_event_types();
+        $this->assertTrue($types['course']);
+        $this->assertFalse($types['group']);
     }
 
     public function test_calendar_get_allowed_event_types_group_no_groups() {
@@ -598,6 +615,12 @@ class core_calendar_lib_testcase extends advanced_testcase {
         // no groups so we shouldn't see a group type.
         $types = calendar_get_allowed_event_types($course->id);
         $this->assertTrue($types['course']);
+        $this->assertFalse($types['group']);
+
+        // Same result applies when not providing a specific course as they are only on one course.
+        $types = calendar_get_allowed_event_types();
+        $this->assertTrue($types['course']);
+        $this->assertFalse($types['group']);
     }
 
     public function test_calendar_get_allowed_event_types_group_access_all_groups() {
@@ -623,7 +646,12 @@ class core_calendar_lib_testcase extends advanced_testcase {
         // the accessallgroups capability.
         $types = calendar_get_allowed_event_types($course1->id);
         $this->assertTrue($types['group']);
+
+        // Same result applies when not providing a specific course as they are only on one course.
+        $types = calendar_get_allowed_event_types();
+        $this->assertTrue($types['group']);
     }
+
     public function test_calendar_get_allowed_event_types_group_no_access_all_groups() {
         $generator = $this->getDataGenerator();
         $user = $generator->create_user();
@@ -642,10 +670,87 @@ class core_calendar_lib_testcase extends advanced_testcase {
         // groups that they are not a member of.
         $types = calendar_get_allowed_event_types($course->id);
         $this->assertFalse($types['group']);
+
+        // Same result applies when not providing a specific course as they are only on one course.
+        $types = calendar_get_allowed_event_types();
+        $this->assertFalse($types['group']);
+
         assign_capability('moodle/calendar:manageentries', CAP_ALLOW, $roleid, $context, true);
         assign_capability('moodle/site:accessallgroups', CAP_ALLOW, $roleid, $context, true);
         $types = calendar_get_allowed_event_types($course->id);
         $this->assertTrue($types['group']);
+
+        // Same result applies when not providing a specific course as they are only on one course.
+        $types = calendar_get_allowed_event_types();
+        $this->assertTrue($types['group']);
+    }
+
+    public function test_calendar_get_allowed_event_types_group_cap_no_groups() {
+        $generator = $this->getDataGenerator();
+        $user = $generator->create_user();
+        $course = $generator->create_course();
+        $context = context_course::instance($course->id);
+        $roleid = $generator->create_role();
+        $group = $generator->create_group(['courseid' => $course->id]);
+        $generator->enrol_user($user->id, $course->id, 'student');
+        $generator->role_assign($roleid, $user->id, $context->id);
+        assign_capability('moodle/calendar:managegroupentries', CAP_ALLOW, $roleid, $context, true);
+
+        $this->setUser($user);
+        $types = calendar_get_allowed_event_types($course->id);
+        $this->assertFalse($types['course']);
+        $this->assertFalse($types['group']);
+
+        // Check without specifying a course (same result as user only has one course).
+        $types = calendar_get_allowed_event_types();
+        $this->assertFalse($types['course']);
+        $this->assertFalse($types['group']);
+    }
+
+    public function test_calendar_get_allowed_event_types_group_cap_has_group() {
+        $generator = $this->getDataGenerator();
+        $user = $generator->create_user();
+        $course = $generator->create_course();
+        $context = context_course::instance($course->id);
+        $roleid = $generator->create_role();
+        $group = $generator->create_group(['courseid' => $course->id]);
+        $generator->enrol_user($user->id, $course->id, 'student');
+        $generator->role_assign($roleid, $user->id, $context->id);
+        groups_add_member($group, $user);
+        assign_capability('moodle/calendar:managegroupentries', CAP_ALLOW, $roleid, $context, true);
+
+        $this->setUser($user);
+        $types = calendar_get_allowed_event_types($course->id);
+        $this->assertFalse($types['course']);
+        $this->assertTrue($types['group']);
+
+        // Check without specifying a course (same result as user only has one course).
+        $types = calendar_get_allowed_event_types();
+        $this->assertFalse($types['course']);
+        $this->assertTrue($types['group']);
+    }
+
+    public function test_calendar_get_allowed_event_types_group_cap_access_all_groups() {
+        $generator = $this->getDataGenerator();
+        $user = $generator->create_user();
+        $course = $generator->create_course();
+        $context = context_course::instance($course->id);
+        $roleid = $generator->create_role();
+        $group = $generator->create_group(['courseid' => $course->id]);
+        $generator->enrol_user($user->id, $course->id, 'student');
+        $generator->role_assign($roleid, $user->id, $context->id);
+        assign_capability('moodle/calendar:managegroupentries', CAP_ALLOW, $roleid, $context, true);
+        assign_capability('moodle/site:accessallgroups', CAP_ALLOW, $roleid, $context, true);
+
+        $this->setUser($user);
+        $types = calendar_get_allowed_event_types($course->id);
+        $this->assertFalse($types['course']);
+        $this->assertTrue($types['group']);
+
+        // Check without specifying a course (same result as user only has one course).
+        $types = calendar_get_allowed_event_types();
+        $this->assertFalse($types['course']);
+        $this->assertTrue($types['group']);
     }
 
     /**