diff --git a/test/api/v3/integration/challenges/GET-challenges_challengeId.test.js b/test/api/v3/integration/challenges/GET-challenges_challengeId.test.js
index 049506570e..6a9cd68429 100644
--- a/test/api/v3/integration/challenges/GET-challenges_challengeId.test.js
+++ b/test/api/v3/integration/challenges/GET-challenges_challengeId.test.js
@@ -63,45 +63,48 @@ describe('GET /challenges/:challengeId', () => {
 
   context('private guild', () => {
     let groupLeader;
+    let challengeLeader;
     let group;
     let challenge;
     let members;
-    let user;
+    let nonMember;
+    let otherMember;
 
     beforeEach(async () => {
-      user = await generateUser();
+      nonMember = await generateUser();
 
       let populatedGroup = await createAndPopulateGroup({
         groupDetails: {type: 'guild', privacy: 'private'},
-        members: 1,
+        members: 2,
       });
 
       groupLeader = populatedGroup.groupLeader;
       group = populatedGroup.group;
       members = populatedGroup.members;
 
-      challenge = await generateChallenge(groupLeader, group);
-      await members[0].post(`/challenges/${challenge._id}/join`);
-      await groupLeader.post(`/challenges/${challenge._id}/join`);
+      challengeLeader = members[0];
+      otherMember = members[1];
+
+      challenge = await generateChallenge(challengeLeader, group);
     });
 
-    it('fails if user doesn\'t have access to the challenge', async () => {
-      await expect(user.get(`/challenges/${challenge._id}`)).to.eventually.be.rejected.and.eql({
+    it('fails if user isn\'t in the guild and isn\'t challenge leader', async () => {
+      await expect(nonMember.get(`/challenges/${challenge._id}`)).to.eventually.be.rejected.and.eql({
         code: 404,
         error: 'NotFound',
         message: t('challengeNotFound'),
       });
     });
 
-    it('should return challenge data', async () => {
-      let chal = await members[0].get(`/challenges/${challenge._id}`);
+    it('returns challenge data for any user in the guild', async () => {
+      let chal = await otherMember.get(`/challenges/${challenge._id}`);
       expect(chal.name).to.equal(challenge.name);
       expect(chal._id).to.equal(challenge._id);
 
       expect(chal.leader).to.eql({
-        _id: groupLeader._id,
-        id: groupLeader._id,
-        profile: {name: groupLeader.profile.name},
+        _id: challengeLeader._id,
+        id: challengeLeader._id,
+        profile: {name: challengeLeader.profile.name},
       });
       expect(chal.group).to.eql({
         _id: group._id,
@@ -114,53 +117,72 @@ describe('GET /challenges/:challengeId', () => {
         leader: groupLeader.id,
       });
     });
+
+    it('returns challenge data if challenge leader isn\'t in the guild or challenge', async () => {
+      await challengeLeader.post(`/groups/${group._id}/leave`);
+      await challengeLeader.sync();
+      expect(challengeLeader.guilds).to.be.empty; // check that leaving worked
+
+      let chal = await challengeLeader.get(`/challenges/${challenge._id}`);
+      expect(chal.name).to.equal(challenge.name);
+      expect(chal._id).to.equal(challenge._id);
+
+      expect(chal.leader).to.eql({
+        _id: challengeLeader._id,
+        id: challengeLeader._id,
+        profile: {name: challengeLeader.profile.name},
+      });
+    });
   });
 
   context('party', () => {
     let groupLeader;
+    let challengeLeader;
     let group;
     let challenge;
     let members;
-    let user;
+    let nonMember;
+    let otherMember;
 
     beforeEach(async () => {
-      user = await generateUser();
+      nonMember = await generateUser();
 
       let populatedGroup = await createAndPopulateGroup({
-        groupDetails: {type: 'party'},
-        members: 1,
+        groupDetails: {type: 'party', privacy: 'private'},
+        members: 2,
       });
 
       groupLeader = populatedGroup.groupLeader;
       group = populatedGroup.group;
       members = populatedGroup.members;
 
-      challenge = await generateChallenge(groupLeader, group);
-      await members[0].post(`/challenges/${challenge._id}/join`);
-      await groupLeader.post(`/challenges/${challenge._id}/join`);
+      challengeLeader = members[0];
+      otherMember = members[1];
+
+      challenge = await generateChallenge(challengeLeader, group);
     });
 
-    it('fails if user doesn\'t have access to the challenge', async () => {
-      await expect(user.get(`/challenges/${challenge._id}`)).to.eventually.be.rejected.and.eql({
+    it('fails if user isn\'t in the party and isn\'t challenge leader', async () => {
+      await expect(nonMember.get(`/challenges/${challenge._id}`)).to.eventually.be.rejected.and.eql({
         code: 404,
         error: 'NotFound',
         message: t('challengeNotFound'),
       });
     });
 
-    it('should return challenge data', async () => {
-      let chal = await members[0].get(`/challenges/${challenge._id}`);
+    it('returns challenge data for any user in the party', async () => {
+      let chal = await otherMember.get(`/challenges/${challenge._id}`);
       expect(chal.name).to.equal(challenge.name);
       expect(chal._id).to.equal(challenge._id);
 
       expect(chal.leader).to.eql({
-        _id: groupLeader._id,
-        id: groupLeader.id,
-        profile: {name: groupLeader.profile.name},
+        _id: challengeLeader._id,
+        id: challengeLeader._id,
+        profile: {name: challengeLeader.profile.name},
       });
       expect(chal.group).to.eql({
         _id: group._id,
-        id: group.id,
+        id: group._id,
         categories: [],
         name: group.name,
         summary: group.name,
@@ -169,5 +191,21 @@ describe('GET /challenges/:challengeId', () => {
         leader: groupLeader.id,
       });
     });
+
+    it('returns challenge data if challenge leader isn\'t in the party or challenge', async () => {
+      await challengeLeader.post('/groups/party/leave');
+      await challengeLeader.sync();
+      expect(challengeLeader.party._id).to.be.undefined; // check that leaving worked
+
+      let chal = await challengeLeader.get(`/challenges/${challenge._id}`);
+      expect(chal.name).to.equal(challenge.name);
+      expect(chal._id).to.equal(challenge._id);
+
+      expect(chal.leader).to.eql({
+        _id: challengeLeader._id,
+        id: challengeLeader._id,
+        profile: {name: challengeLeader.profile.name},
+      });
+    });
   });
 });
diff --git a/test/api/v3/integration/challenges/GET-challenges_challengeId_members.test.js b/test/api/v3/integration/challenges/GET-challenges_challengeId_members.test.js
index 71aa643869..2b0e006d38 100644
--- a/test/api/v3/integration/challenges/GET-challenges_challengeId_members.test.js
+++ b/test/api/v3/integration/challenges/GET-challenges_challengeId_members.test.js
@@ -1,6 +1,7 @@
 import {
   generateUser,
   generateGroup,
+  createAndPopulateGroup,
   generateChallenge,
   translate as t,
 } from '../../../../helpers/api-integration/v3';
@@ -10,7 +11,7 @@ describe('GET /challenges/:challengeId/members', () => {
   let user;
 
   beforeEach(async () => {
-    user = await generateUser();
+    user = await generateUser({ balance: 1 });
   });
 
   it('validates optional req.query.lastId to be an UUID', async () => {
@@ -21,7 +22,7 @@ describe('GET /challenges/:challengeId/members', () => {
     });
   });
 
-  it('fails if challenge doesn\'t exists', async () => {
+  it('fails if challenge doesn\'t exist', async () => {
     await expect(user.get(`/challenges/${generateUUID()}/members`)).to.eventually.be.rejected.and.eql({
       code: 404,
       error: 'NotFound',
@@ -29,8 +30,8 @@ describe('GET /challenges/:challengeId/members', () => {
     });
   });
 
-  it('fails if user doesn\'t have access to the challenge', async () => {
-    let group = await generateGroup(user);
+  it('fails if user isn\'t in the private group and isn\'t challenge leader', async () => {
+    let group = await generateGroup(user, {type: 'party', privacy: 'private'});
     let challenge = await generateChallenge(user, group);
     let anotherUser = await generateUser();
 
@@ -41,6 +42,27 @@ describe('GET /challenges/:challengeId/members', () => {
     });
   });
 
+  it('works if user isn\'t in the private group but is challenge leader', async () => {
+    let populatedGroup = await createAndPopulateGroup({
+      groupDetails: {type: 'party', privacy: 'private'},
+      members: 1,
+    });
+    let groupLeader = populatedGroup.groupLeader;
+    let challengeLeader = populatedGroup.members[0];
+    let challenge = await generateChallenge(challengeLeader, populatedGroup.group);
+    await groupLeader.post(`/challenges/${challenge._id}/join`);
+    await challengeLeader.post('/groups/party/leave');
+    await challengeLeader.sync();
+    expect(challengeLeader.party._id).to.be.undefined; // check that leaving worked
+
+    let res = await challengeLeader.get(`/challenges/${challenge._id}/members`);
+    expect(res[0]).to.eql({
+      _id: groupLeader._id,
+      id: groupLeader._id,
+      profile: {name: groupLeader.profile.name},
+    });
+  });
+
   it('works with challenges belonging to public guild', async () => {
     let leader = await generateUser({balance: 4});
     let group = await generateGroup(leader, {type: 'guild', privacy: 'public', name: generateUUID()});
diff --git a/test/api/v3/integration/challenges/POST-challenges.test.js b/test/api/v3/integration/challenges/POST-challenges.test.js
index 0176a729ff..b53c3750b1 100644
--- a/test/api/v3/integration/challenges/POST-challenges.test.js
+++ b/test/api/v3/integration/challenges/POST-challenges.test.js
@@ -94,16 +94,6 @@ describe('POST /challenges', () => {
       });
     });
 
-    it('returns an error when non-leader member creates a challenge in leaderOnly group', async () => {
-      await expect(groupMember.post('/challenges', {
-        group: group._id,
-      })).to.eventually.be.rejected.and.eql({
-        code: 401,
-        error: 'NotAuthorized',
-        message: t('onlyGroupLeaderChal'),
-      });
-    });
-
     it('allows non-leader member to create a challenge', async () => {
       let populatedGroup = await createAndPopulateGroup({
         members: 1,
diff --git a/test/api/v3/integration/challenges/POST-challenges_challengeId_join.test.js b/test/api/v3/integration/challenges/POST-challenges_challengeId_join.test.js
index 6c403d05ad..1ca9a434c3 100644
--- a/test/api/v3/integration/challenges/POST-challenges_challengeId_join.test.js
+++ b/test/api/v3/integration/challenges/POST-challenges_challengeId_join.test.js
@@ -46,7 +46,7 @@ describe('POST /challenges/:challengeId/join', () => {
       await groupLeader.post(`/challenges/${challenge._id}/join`);
     });
 
-    it('returns an error when user doesn\'t have permissions to access the challenge', async () => {
+    it('returns an error when user isn\'t in the private group and isn\'t challenge leader', async () => {
       let unauthorizedUser = await generateUser();
 
       await expect(unauthorizedUser.post(`/challenges/${challenge._id}/join`)).to.eventually.be.rejected.and.eql({
@@ -56,6 +56,16 @@ describe('POST /challenges/:challengeId/join', () => {
       });
     });
 
+    it('succeeds when user isn\'t in the private group but is challenge leader', async () => {
+      await groupLeader.post(`/challenges/${challenge._id}/leave`);
+      await groupLeader.post(`/groups/${group._id}/leave`);
+      await groupLeader.sync();
+      expect(groupLeader.guilds).to.be.empty; // check that leaving worked
+
+      let res = await groupLeader.post(`/challenges/${challenge._id}/join`);
+      expect(res.name).to.equal(challenge.name);
+    });
+
     it('returns challenge data', async () => {
       let res = await authorizedUser.post(`/challenges/${challenge._id}/join`);
 
diff --git a/website/server/controllers/api-v3/challenges.js b/website/server/controllers/api-v3/challenges.js
index 7419949ea0..fe705d3a1a 100644
--- a/website/server/controllers/api-v3/challenges.js
+++ b/website/server/controllers/api-v3/challenges.js
@@ -251,7 +251,7 @@ api.joinChallenge = {
     if (challenge.isMember(user)) throw new NotAuthorized(res.t('userAlreadyInChallenge'));
 
     let group = await Group.getGroup({user, groupId: challenge.group, fields: basicGroupFields, optionalMembership: true});
-    if (!group || !challenge.hasAccess(user, group)) throw new NotFound(res.t('challengeNotFound'));
+    if (!group || !challenge.canJoin(user, group)) throw new NotFound(res.t('challengeNotFound'));
 
     challenge.memberCount += 1;
 
diff --git a/website/server/models/challenge.js b/website/server/models/challenge.js
index a094814fe7..bb18888928 100644
--- a/website/server/models/challenge.js
+++ b/website/server/models/challenge.js
@@ -66,6 +66,11 @@ schema.statics.sanitizeUpdate = function sanitizeUpdate (updateObj) {
   return this.sanitize(updateObj, noUpdate);
 };
 
+// Returns true if user is the leader/owner of the challenge
+schema.methods.isLeader = function isChallengeLeader (user) {
+  return this.leader === user._id;
+};
+
 // Returns true if user is a member of the challenge
 schema.methods.isMember = function isChallengeMember (user) {
   return user.challenges.indexOf(this._id) !== -1;
@@ -73,20 +78,21 @@ schema.methods.isMember = function isChallengeMember (user) {
 
 // Returns true if the user can modify (close, selectWinner, ...) the challenge
 schema.methods.canModify = function canModifyChallenge (user) {
-  return user.contributor.admin || this.leader === user._id;
+  return user.contributor.admin || this.isLeader(user);
 };
 
-// Returns true if user has access to the challenge (can join)
-schema.methods.hasAccess = function hasAccessToChallenge (user, group) {
+// Returns true if user can join the challenge
+schema.methods.canJoin = function canJoinChallenge (user, group) {
   if (group.type === 'guild' && group.privacy === 'public') return true;
+  if (this.isLeader(user)) return true; // for when leader has left private group that contains the challenge
   return user.getGroups().indexOf(this.group) !== -1;
 };
 
 // Returns true if user can view the challenge
-// Different from hasAccess because you can see challenges of groups you've been removed from if you're partecipating in them
+// Different from canJoin because you can see challenges of groups you've been removed from if you're participating in them
 schema.methods.canView = function canViewChallenge (user, group) {
   if (this.isMember(user)) return true;
-  return this.hasAccess(user, group);
+  return this.canJoin(user, group);
 };
 
 // Sync challenge to user, including tasks and tags.