diff --git a/README.md b/README.md
index ad0b8d8b..d17997bc 100644
--- a/README.md
+++ b/README.md
@@ -304,6 +304,8 @@ Changelog
   * Add `Instagram.merge_scraped_comments()`.
 * ActivityStreams 2:
   * Handle error when `type` isn't a string.
+* Reddit:
+  * Implement `get_activities()` to fetch posts by the current user or a user specified with `user_id`.
 
 ### 3.2 - 2021-09-15
 * `Source.original_post_discovery`: add new `include_reserved_hosts` kwarg, defaults to `True`.
diff --git a/granary/reddit.py b/granary/reddit.py
index 54e5b1bf..5c8fd577 100644
--- a/granary/reddit.py
+++ b/granary/reddit.py
@@ -251,7 +251,7 @@ def _fetch_replies(self, r, activities):
       }
 
   def get_activities_response(self, user_id=None, group_id=None, app_id=None,
-                              activity_id=None, start_index=0, count=0,
+                              activity_id=None, start_index=0, count=None,
                               etag=None, min_id=None, cache=None,
                               fetch_replies=False, fetch_likes=False,
                               fetch_shares=False, fetch_events=False,
@@ -260,16 +260,21 @@ def get_activities_response(self, user_id=None, group_id=None, app_id=None,
 
     Currently only implements activity_id, search_query and fetch_replies.
     """
-    activities = []
     r = self.get_reddit_api()
 
     if activity_id:
-      subm = r.submission(id=activity_id)
-      activities.append(self.praw_to_activity(subm, 'submission'))
+      submissions = [r.submission(id=activity_id)]
     elif search_query:
-      sr = r.subreddit('all')
-      subms = sr.search(search_query, sort='new')
-      activities.extend([self.praw_to_activity(subm, 'submission') for subm in subms])
+      submissions = r.subreddit('all').search(search_query, sort='new', limit=count)
+    else:
+      # Oddly user.me() returns None when in read only mode
+      # https://praw.readthedocs.io/en/stable/code_overview/reddit/user.html#praw.models.User.me
+      r.read_only = False
+      redditor = r.redditor(user_id) if user_id else r.user.me()
+      r.read_only = True
+      submissions = redditor.submissions.new(limit=count)
+
+    activities = [self.praw_to_activity(s, 'submission') for s in submissions]
 
     if fetch_replies:
       self._fetch_replies(r, activities)
diff --git a/granary/tests/test_reddit.py b/granary/tests/test_reddit.py
index 8b6d87f7..262007bc 100644
--- a/granary/tests/test_reddit.py
+++ b/granary/tests/test_reddit.py
@@ -230,6 +230,15 @@ def test_post_id(self):
       'lhzukq',
       self.reddit.post_id('https://www.reddit.com/r/xyz/comments/lhzukq/abc/'))
 
+  # TODO
+  # def test_get_activities_default_user(self):
+  #   self.api.user.me().submissions.new(limit=None).AndReturn(
+  #     [self.submission_selftext, self.submission_link])
+  #   self.mox.ReplayAll()
+
+  #   self.assert_equals([ACTIVITY_WITH_SELFTEXT, ACTIVITY_WITH_LINK],
+  #                      self.reddit.get_activities())
+
   def test_get_activities_activity_id(self):
     self.api.submission(id='abc').AndReturn(self.submission_selftext)
     self.mox.ReplayAll()
@@ -241,7 +250,7 @@ def test_get_activities_search_query(self):
     subreddit = self.mox.CreateMock(praw.models.Subreddit)
     self.mox.StubOutWithMock(self.api, 'subreddit')
     self.api.subreddit('all').AndReturn(subreddit)
-    subreddit.search('foo bar', sort='new').AndReturn(
+    subreddit.search('foo bar', sort='new', limit=None).AndReturn(
       [self.submission_selftext, self.submission_link])
     self.mox.ReplayAll()