Collaborating with External Users in Microsoft Teams

This is a brief guide showing how to collaborate with external users in Microsoft Teams.

Federation vs Guest Access

There are two ways of collaborating with external users in Teams: Federation (external access) and Guest access.

Feature	Federation	Guest access (requires tenant switching)
Chat	Yes (own tenant)	Yes
Call	Yes (own tenant)	Yes
Add to Teams	No	Yes
Share files	No	Yes

Recommendations:

• If you just want to call and chat, use federation.
• If you need to add external users to Teams, use Guest access.
• If you need both, use both.

Note that although you can call/chat with Guests, because this requires tenant switching, the external user will likely not see the call or chat notification since they will be in their own tenant.

Federation

Federation (also known as external access) is simpler and allows chat and calls with external users directly. Domains have to be authorised and added first.

To communicate with an external user:

1. In Teams, click on Chat, then New chat.
2. Type in the user’s external email address.
3. Choose Search externally.
4. Click on the user’s name (External).

The external user will see notifications pop up in their Teams client as normal. Communication is two-way.

Guest Access

This is required if you need to add an external user to a Team, rather than just chat or call.

To add a Guest to a Team:

1. In Teams, click on Teams, then the three dots next to your Team.
2. Choose Add member.
3. Click Add as a guest, then Add.

The external user will receive an email and can accept using their own credentials. They may need to set up MFA depending on your Azure AD external access and conditional access policies.

Tenant switching: The external user will need to switch tenants in Teams to view the Team. This is done by clicking on the company name in the top right and choosing the external company.

More Information

For more details, see Microsoft’s documentation on external access.