diff --git a/app/lib/express.js b/app/lib/express.js
index 1e453fc..b24ac57 100644
--- a/app/lib/express.js
+++ b/app/lib/express.js
@@ -501,9 +501,13 @@ router.get(
 
 const communityData = (req) => {
   const name = req.params.name;
-  return queries.getCommunityMembers(name).then((members) => ({
+  return Promise.all([
+    queries.getCommunityMembers(name),
+    queries.isMember(req.context.profile.id, name),
+  ]).then(([members, isMember]) => ({
     name,
     members,
+    isMember,
   }));
 };
 
@@ -558,6 +562,38 @@ router.post("/communities/:name/new", async (req, res) => {
   res.redirect(`/communities/${name}/${topic.key.replace("%", "")}`);
 });
 
+router.post("/communities/:name/join", async (req, res) => {
+  const name = req.params.name;
+
+  await ssb.client().identities.publishAs({
+    id: req.context.profile.id,
+    private: false,
+    content: {
+      type: "channel",
+      channel: name,
+      subscribed: true,
+    },
+  });
+
+  res.redirect(`/communities/${name}`);
+});
+
+router.post("/communities/:name/leave", async (req, res) => {
+  const name = req.params.name;
+
+  await ssb.client().identities.publishAs({
+    id: req.context.profile.id,
+    private: false,
+    content: {
+      type: "channel",
+      channel: name,
+      subscribed: false,
+    },
+  });
+
+  res.redirect(`/communities/${name}`);
+});
+
 router.post("/communities/:name/:key(*)/publish", async (req, res) => {
   const name = req.params.name;
   const key = req.params.key;
diff --git a/app/lib/mobile-routes.js b/app/lib/mobile-routes.js
index 8bfda6d..f910148 100644
--- a/app/lib/mobile-routes.js
+++ b/app/lib/mobile-routes.js
@@ -94,13 +94,14 @@ module.exports.setupRoutes = (router) => {
     async (req, res) => {
       const name = req.params.name;
 
-      const [posts, members] = await Promise.all([
+      const [posts, members, isMember] = await Promise.all([
         queries.getCommunityPosts(name),
         queries.getCommunityMembers(name),
+        queries.isMember(req.context.profile.id, name),
       ]);
 
       res.render("mobile/communities/community", {
-        community: { name, members },
+        community: { name, members, isMember },
         posts,
         layout: "mobile/_layout",
       });
diff --git a/app/lib/queries.js b/app/lib/queries.js
index 6cb23b7..a36b4f1 100644
--- a/app/lib/queries.js
+++ b/app/lib/queries.js
@@ -8,7 +8,8 @@ const debugPosts = require("debug")("queries:posts"),
   debugProfile = require("debug")("queries:profile"),
   debugCommunities = require("debug")("queries:communities"),
   debugCommunityMembers = require("debug")("queries:communityMembers"),
-  debugCommunityPosts = require("debug")("queries:communityPosts");
+  debugCommunityPosts = require("debug")("queries:communityPosts"),
+  debugCommunityIsMember = require("debug")("queries:communityIsMember");
 const paramap = require("pull-paramap");
 const { promisePull, mapValues } = require("./utils");
 const ssb = require("./ssb-client");
@@ -450,6 +451,32 @@ const getCommunities = async () => {
   return communities;
 };
 
+const isMember = async (id, channel) => {
+  debugCommunityIsMember("Fetching");
+  const [lastSubscription] = await promisePull(
+    ssb.client().query.read({
+      reverse: true,
+      limit: 1,
+      query: [
+        {
+          $filter: {
+            value: {
+              author: id,
+              content: {
+                type: "channel",
+                channel: channel,
+              },
+            },
+          },
+        },
+      ],
+    })
+  );
+  debugCommunityIsMember("Done");
+
+  return lastSubscription && lastSubscription.value.content.subscribed;
+};
+
 const getCommunityMembers = async (name) => {
   debugCommunityMembers("Fetching");
 
@@ -472,10 +499,22 @@ const getCommunityMembers = async (name) => {
     }),
     paramap(mapProfiles)
   );
+  const dedupMembers = {};
+  for (const member of communityMembers) {
+    const author = member.value.author;
+    if (dedupMembers[author]) continue;
+    dedupMembers[author] = member;
+  }
+  const onlySubscribedMembers = Object.values(dedupMembers).filter(
+    (x) => x.value.content.subscribed
+  );
+  const memberProfiles = onlySubscribedMembers.map(
+    (x) => x.value.authorProfile
+  );
 
   debugCommunityMembers("Done");
 
-  return communityMembers.map((x) => x.value.authorProfile);
+  return memberProfiles;
 };
 
 const getPostWithReplies = async (channel, key) => {
@@ -611,4 +650,5 @@ module.exports = {
   getPostWithReplies,
   progress,
   autofollow,
+  isMember,
 };
diff --git a/app/views/communities/_layout.ejs b/app/views/communities/_layout.ejs
index c5f93db..572d21b 100644
--- a/app/views/communities/_layout.ejs
+++ b/app/views/communities/_layout.ejs
@@ -6,8 +6,8 @@
   }
 </style>
 
-<div style="background: #9b5f5f; padding: 50px; border-radius: 5px 5px 0 0">
-  <div style="max-width: 1200px; margin: 0 auto">
+<div style="background: #9b5f5f; padding: 14px; border-radius: 5px 5px 0 0">
+  <div style="max-width: 1200px; margin: 0 auto; padding: 36px;">
     <h1 style="font-size: 60px">
       <a href="/communities/<%= community.name %>" style="color: #FFF; text-decoration: none;">
         #<%= community.name %>
@@ -19,7 +19,12 @@
 <div style="max-width: 1200px; margin: 0 auto; border-radius: 0 0 5px 5px">
   <div class="columns">
     <div class="friends-communities" style="border-radius: 0">
-      <h2>Members</h2>
+      <div style="display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px;">
+        <h2 style="margin: 0;">Members</h2>
+        <div>
+          <%- include('../shared/_join_button') %>
+        </div>
+      </div>
       <%- include('../_friends', { friends: community.members }) %>
     </div>
     <div class="wall">
diff --git a/app/views/mobile/communities/community.ejs b/app/views/mobile/communities/community.ejs
index 1389a60..1b1a42e 100644
--- a/app/views/mobile/communities/community.ejs
+++ b/app/views/mobile/communities/community.ejs
@@ -1,9 +1,12 @@
 <div class="pink-background" style="flex-grow: 0;">
-  <h1>
-    <a href="/communities/<%= community.name %>" style="color: #600; text-decoration: none;">
-      #<%= community.name %>
-    </a>
-  </h1>
+  <div style="display: flex; justify-content: space-between;">
+    <h1>
+      <a href="/communities/<%= community.name %>" style="color: #600; text-decoration: none;">
+        #<%= community.name %>
+      </a>
+    </h1>
+    <%- include('../../shared/_join_button') %>
+  </div>
   <a href="/mobile/communities/<%= community.name %>/new" class="compose-new-button" style="background: #fbb">
     <div style="font-size: 40px; color: #FFF">+</div>
   </a>
@@ -19,7 +22,7 @@
 <div class="tab-content">
   <div class="tab-item js-tab-item">
     <% posts.map(post => { %>
-      <a href="/communities/<%= community.name %>/<%= post.key.replace("%", "") %>" class="columns community-topic-link">
+      <a href="/mobile/communities/<%= community.name %>/<%= post.key.replace("%", "") %>" class="columns community-topic-link">
         <div class="community-topic-name">
           <%- topicTitle(post.value) %>
         </div>
diff --git a/app/views/shared/_join_button.ejs b/app/views/shared/_join_button.ejs
new file mode 100644
index 0000000..fdf2452
--- /dev/null
+++ b/app/views/shared/_join_button.ejs
@@ -0,0 +1,9 @@
+<% if (community.isMember) { %>
+  <form action="/communities/<%= community.name %>/leave" method="POST">
+    <input type="submit" value="Leave" />
+  </form>
+<% } else { %>
+  <form action="/communities/<%= community.name %>/join" method="POST">
+    <input type="submit" value="Join" />
+  </form>
+<% } %>
\ No newline at end of file