diff --git a/common/djangoapps/enrollment/api.py b/common/djangoapps/enrollment/api.py
index 25047219f7..2e352a7581 100644
--- a/common/djangoapps/enrollment/api.py
+++ b/common/djangoapps/enrollment/api.py
@@ -7,6 +7,8 @@ import importlib
 import logging
 from django.conf import settings
 from django.core.cache import cache
+from opaque_keys.edx.keys import CourseKey
+
 from course_modes.models import CourseMode
 from enrollment import errors
 
@@ -372,9 +374,8 @@ def _default_course_mode(course_id):
     Returns:
         str
     """
-    course_enrollment_info = _data_api().get_course_enrollment_info(course_id, include_expired=False)
-    course_modes = course_enrollment_info["course_modes"]
-    available_modes = [m['slug'] for m in course_modes]
+    course_modes = CourseMode.modes_for_course(CourseKey.from_string(course_id))
+    available_modes = [m.slug for m in course_modes]
 
     if CourseMode.DEFAULT_MODE_SLUG in available_modes:
         return CourseMode.DEFAULT_MODE_SLUG
diff --git a/common/djangoapps/enrollment/tests/test_api.py b/common/djangoapps/enrollment/tests/test_api.py
index 3d41d24743..95b441d157 100644
--- a/common/djangoapps/enrollment/tests/test_api.py
+++ b/common/djangoapps/enrollment/tests/test_api.py
@@ -1,6 +1,8 @@
 """
 Tests for student enrollment.
 """
+from mock import patch, Mock
+
 import ddt
 from django.core.cache import cache
 from nose.tools import raises
@@ -67,12 +69,15 @@ class EnrollmentTest(TestCase):
     def test_enroll_no_mode_success(self, course_modes, expected_mode):
         # Add a fake course enrollment information to the fake data API
         fake_data_api.add_course(self.COURSE_ID, course_modes=course_modes)
-        # Enroll in the course and verify the URL we get sent to
-        result = api.add_enrollment(self.USERNAME, self.COURSE_ID)
-        self.assertIsNotNone(result)
-        self.assertEquals(result['student'], self.USERNAME)
-        self.assertEquals(result['course']['course_id'], self.COURSE_ID)
-        self.assertEquals(result['mode'], expected_mode)
+        with patch('enrollment.api.CourseMode.modes_for_course') as mock_modes_for_course:
+            mock_course_modes = [Mock(slug=mode) for mode in course_modes]
+            mock_modes_for_course.return_value = mock_course_modes
+            # Enroll in the course and verify the URL we get sent to
+            result = api.add_enrollment(self.USERNAME, self.COURSE_ID)
+            self.assertIsNotNone(result)
+            self.assertEquals(result['student'], self.USERNAME)
+            self.assertEquals(result['course']['course_id'], self.COURSE_ID)
+            self.assertEquals(result['mode'], expected_mode)
 
     @ddt.data(
         ['professional'],
diff --git a/common/djangoapps/enrollment/views.py b/common/djangoapps/enrollment/views.py
index 110df7e906..69aea5996c 100644
--- a/common/djangoapps/enrollment/views.py
+++ b/common/djangoapps/enrollment/views.py
@@ -520,7 +520,7 @@ class EnrollmentListView(APIView, ApiKeyPermissionMixIn):
                 }
             )
 
-        mode = request.data.get('mode', CourseMode.DEFAULT_MODE_SLUG)
+        mode = request.data.get('mode')
 
         has_api_key_permissions = self.has_api_key_permissions(request)
 
@@ -532,7 +532,7 @@ class EnrollmentListView(APIView, ApiKeyPermissionMixIn):
             # other users, do not let them deduce the existence of an enrollment.
             return Response(status=status.HTTP_404_NOT_FOUND)
 
-        if mode != CourseMode.DEFAULT_MODE_SLUG and not has_api_key_permissions:
+        if mode not in (CourseMode.AUDIT, CourseMode.HONOR, None) and not has_api_key_permissions:
             return Response(
                 status=status.HTTP_403_FORBIDDEN,
                 data={
diff --git a/common/djangoapps/student/models.py b/common/djangoapps/student/models.py
index de736b7f9f..d3976288a4 100644
--- a/common/djangoapps/student/models.py
+++ b/common/djangoapps/student/models.py
@@ -47,6 +47,7 @@ from xmodule_django.models import CourseKeyField, NoneToEmptyManager
 
 from certificates.models import GeneratedCertificate
 from course_modes.models import CourseMode
+from enrollment.api import _default_course_mode
 import lms.lib.comment_client as cc
 from openedx.core.djangoapps.commerce.utils import ecommerce_api_client, ECOMMERCE_DATE_FORMAT
 from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
@@ -1090,7 +1091,7 @@ class CourseEnrollment(models.Model):
                 )
 
     @classmethod
-    def enroll(cls, user, course_key, mode=CourseMode.DEFAULT_MODE_SLUG, check_access=False):
+    def enroll(cls, user, course_key, mode=None, check_access=False):
         """
         Enroll a user in a course. This saves immediately.
 
@@ -1124,6 +1125,8 @@ class CourseEnrollment(models.Model):
 
         Also emits relevant events for analytics purposes.
         """
+        if mode is None:
+            mode = _default_course_mode(unicode(course_key))
         # All the server-side checks for whether a user is allowed to enroll.
         try:
             course = CourseOverview.get_from_id(course_key)
@@ -1165,7 +1168,7 @@ class CourseEnrollment(models.Model):
         return enrollment
 
     @classmethod
-    def enroll_by_email(cls, email, course_id, mode=CourseMode.DEFAULT_MODE_SLUG, ignore_errors=True):
+    def enroll_by_email(cls, email, course_id, mode=None, ignore_errors=True):
         """
         Enroll a user in a course given their email. This saves immediately.
 
diff --git a/lms/djangoapps/instructor/enrollment.py b/lms/djangoapps/instructor/enrollment.py
index e134964fa2..31f0f3ff25 100644
--- a/lms/djangoapps/instructor/enrollment.py
+++ b/lms/djangoapps/instructor/enrollment.py
@@ -119,7 +119,7 @@ def enroll_email(course_id, student_email, auto_enroll=False, email_students=Fal
         if CourseMode.is_white_label(course_id):
             course_mode = CourseMode.DEFAULT_SHOPPINGCART_MODE_SLUG
         else:
-            course_mode = CourseMode.DEFAULT_MODE_SLUG
+            course_mode = None
 
         if previous_state.enrollment:
             course_mode = previous_state.mode