Communicate with users from other organizations in Microsoft Teams

When you need to communicate and collaborate with people outside your organization, Microsoft Teams gives you two different ways to make that happen. The first – external access (federation) – lets you find, call, and chat with users in other domains (for example, contoso.com). The second – guest access – lets you add individuals to your teams, as guests, using their email address. You can collaborate with guests as you would with any other users in your organization.

You can use both external access and guest access if you want - one doesn't preclude the other.

At a high level, here’s how to choose (for a detailed comparison, jump down to Compare external and guest access):

External access

Use external access (federation) when you need a solution that lets external users in other domains find, call, chat, and set up meetings with you. External users have no access to your organization's teams or team resources. Choose external access when you want to communicate with external users who are still on Skype for Business (online or on premises) or Skype (coming in early 2020).

External access is turned on by default in Teams, which means your org can communicate with all external domains. The Teams admin can turn it off or specify which domains to include (or exclude). To learn more, read Manage external access.

If you want external users to have access to teams and channels, guest access might be a better way to go.

Guest access

Use guest access to add an individual user (regardless of domain) to a team, where they can chat, call, meet, and collaborate on organization files (stored in SharePoint or OneDrive for Business), using Office 365 apps such as Word, Excel, or PowerPoint. A guest user can be given nearly all the same Teams capabilities as a native team member. To learn more, read Guest access in Teams.

  • Guests are added to your organization’s Active Directory.
  • To communicate with a guest, the guest has to be signed in to Teams using their guest account. This means that a guest may have to sign out of their own Teams account to sign in to your Teams account.
  • Guest users have access to more resources in Teams - such as files, teams, and channels - than external-access (federated) users.
  • The Teams admin controls everything that a guest can (or can’t) do in the Teams admin center. To learn more, read Manage guest access.

If you're ready to turn on guest access in your organization, start with the Guest access checklist.

Compare external and guest access

Feature External access users Guest access users
User can chat with someone in another company Yes Yes
User can call someone in another company Yes Yes
User can see if someone from another company is available for call or chat Yes Yes1
User can search for users across external tenants Yes2 No
User can share files No Yes
User can access Teams resources No Yes
User can be added to a group chat No Yes
User can be invited to a meeting Yes Yes
Additional users can be added to a chat with an external user No3 N/A
User is identified as an external party Yes Yes
Presence is displayed Yes Yes
Out of office message is shown No Yes
Individual user can be blocked No Yes
@mentions are supported Yes4 Yes
Make private calls Yes Yes
Allow IP video Yes Yes
Screen sharing mode Yes4 Yes
Allow meet now No Yes
Edit sent messages Yes4 Yes
Can delete sent messages Yes4 Yes
Use Giphy in conversation Yes4 Yes
Use memes in conversation Yes4 Yes
Use stickers in conversation Yes4 Yes

1 Provided that the user has been added as a guest and is signed in as a guest to the guest tenant.
2 Only by email or Session Initiation Protocol (SIP) address.
3 External (federated) chat is 1:1 only.
4 Supported for 1:1 chat for Teams Only to Teams Only users from two different organizations.

External access in Teams

Guest access in Teams