diff --git a/test/api/v3/integration/groups/POST-groups_groupId_join.test.js b/test/api/v3/integration/groups/POST-groups_groupId_join.test.js
index d24a03cb7e..d20c8b830d 100644
--- a/test/api/v3/integration/groups/POST-groups_groupId_join.test.js
+++ b/test/api/v3/integration/groups/POST-groups_groupId_join.test.js
@@ -1,6 +1,7 @@
 import {
   generateUser,
   createAndPopulateGroup,
+  checkExistence,
   translate as t,
 } from '../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
@@ -185,6 +186,23 @@ describe('POST /group/:groupId/join', () => {
         await expect(user.get('/user')).to.eventually.have.deep.property('items.quests.basilist', 2);
       });
 
+      it('deletes previous party where the user was the only member', async () => {
+        let userToInvite = await generateUser();
+        let oldParty = await userToInvite.post('/groups', { // add user to a party
+          name: 'Another Test Party',
+          type: 'party',
+        });
+
+        await expect(checkExistence('groups', oldParty._id)).to.eventually.equal(true);
+        await user.post(`/groups/${party._id}/invite`, {
+          uuids: [userToInvite._id],
+        });
+        await userToInvite.post(`/groups/${party._id}/join`);
+
+        await expect(user.get('/user')).to.eventually.have.deep.property('party._id', party._id);
+        await expect(checkExistence('groups', oldParty._id)).to.eventually.equal(false);
+      });
+
       xit('invites joining member to active quest', async () => {
         // TODO start quest
 
diff --git a/test/api/v3/integration/groups/POST-groups_invite.test.js b/test/api/v3/integration/groups/POST-groups_invite.test.js
index 42719c0fcd..55c25d9153 100644
--- a/test/api/v3/integration/groups/POST-groups_invite.test.js
+++ b/test/api/v3/integration/groups/POST-groups_invite.test.js
@@ -290,12 +290,14 @@ describe('Post /groups/:groupId/invite', () => {
       });
     });
 
-    it('returns an error when invited user is already in the party', async () => {
+    it('returns an error when invited user is already in a party of more than 1 member', async () => {
       let userToInvite = await generateUser();
+      let userToInvite2 = await generateUser();
       await inviter.post(`/groups/${party._id}/invite`, {
-        uuids: [userToInvite._id],
+        uuids: [userToInvite._id, userToInvite2._id],
       });
       await userToInvite.post(`/groups/${party._id}/join`);
+      await userToInvite2.post(`/groups/${party._id}/join`);
 
       await expect(inviter.post(`/groups/${party._id}/invite`, {
         uuids: [userToInvite._id],
@@ -306,5 +308,18 @@ describe('Post /groups/:groupId/invite', () => {
         message: t('userAlreadyInAParty'),
       });
     });
+
+    it('allow inviting an user to a party if he\'s partying solo', async () => {
+      let userToInvite = await generateUser();
+      await userToInvite.post('/groups', { // add user to a party
+        name: 'Another Test Party',
+        type: 'party',
+      });
+
+      await inviter.post(`/groups/${party._id}/invite`, {
+        uuids: [userToInvite._id],
+      });
+      expect((await userToInvite.get('/user')).invitations.party.id).to.equal(party._id);
+    });
   });
 });
diff --git a/website/src/controllers/api-v3/groups.js b/website/src/controllers/api-v3/groups.js
index 48e06a752a..0c6a35330e 100644
--- a/website/src/controllers/api-v3/groups.js
+++ b/website/src/controllers/api-v3/groups.js
@@ -238,10 +238,18 @@ api.joinGroup = {
       if (group.quest.key && !group.quest.active) {
         user.party.quest.RSVPNeeded = true;
         user.party.quest.key = group.quest.key;
+        user.party.quest.progress = undefined; // Make sure to reset progress from ay previous quest
         group.quest.members[user._id] = undefined;
         group.markModified('quest.members');
       }
 
+      // If user was in a different party (when partying solo you can be invited to a new party)
+      // make him leave that party before doing anything
+      if (user.party._id) {
+        let userPreviousParty = await Group.getGroup({user, groupId: user.party._id});
+        if (userPreviousParty) await userPreviousParty.leave(user);
+      }
+
       user.party._id = group._id; // Set group as user's party
 
       isUserInvited = true;
@@ -425,7 +433,7 @@ api.removeGroupMember = {
 };
 
 async function _inviteByUUID (uuid, group, inviter, req, res) {
-  // @TODO: Add Push Notifications
+  // TODO: Add Push Notifications
   let userToInvite = await User.findById(uuid).exec();
 
   if (!userToInvite) {
@@ -444,11 +452,14 @@ async function _inviteByUUID (uuid, group, inviter, req, res) {
     if (!_.isEmpty(userToInvite.invitations.party)) {
       throw new NotAuthorized(res.t('userAlreadyPendingInvitation'));
     }
+
     if (userToInvite.party._id) {
-      throw new NotAuthorized(res.t('userAlreadyInAParty'));
+      let userParty = await Group.getGroup({user: userToInvite, groupId: 'party', fields: 'memberCount'});
+
+      // Allow user to be invited to a new party when they're partying solo
+      if (userParty.memberCount !== 1) throw new NotAuthorized(res.t('userAlreadyInAParty'));
     }
-    // @TODO: Why was this here?
-    // req.body.type in 'guild', 'party'
+
     userToInvite.invitations.party = {id: group._id, name: group.name, inviter: inviter._id};
   }
 
diff --git a/website/src/models/group.js b/website/src/models/group.js
index d5d83b19b1..8b11a57081 100644
--- a/website/src/models/group.js
+++ b/website/src/models/group.js
@@ -118,10 +118,10 @@ schema.statics.getGroup = function getGroup (options = {}) {
   let query;
 
   // When optionalMembership is true it's not required for the user to be a member of the group
-  if (optionalMembership === true) {
-    query = {_id: groupId};
-  } else if (groupId === 'party' || user.party._id === groupId) {
+  if (groupId === 'party' || user.party._id === groupId) {
     query = {type: 'party', _id: user.party._id};
+  } else if (optionalMembership === true) {
+    query = {_id: groupId};
   } else if (user.guilds.indexOf(groupId) !== -1) {
     query = {type: 'guild', _id: groupId};
   } else {