You can add an external contact to Microsoft Teams in two ways: by starting a direct chat using their email address, or by adding them as a guest to a specific team. Which method you use depends on whether you just need to message someone or want to give them ongoing access to a team’s channels and files. Both require your organization’s admin to have external communication enabled.
Start a Chat With an External Contact
The fastest way to connect with someone outside your organization is through a one-on-one chat. On the left side of Teams, select Chat, then click the New Chat icon. In the “To” field, type the person’s full email address. If their name appears in the results below the search bar, select it. If no name match comes up, type the full email address and wait for results to populate.
Once you see the contact, type your message in the text box at the bottom and hit Send. That’s it. The conversation will now appear in your chat list, and you can return to it anytime without re-entering the email address. External contacts typically show a small label like “External” next to their name so you can distinguish them from people inside your organization.
This method works with anyone whose organization also uses Teams and allows external communication. If the person uses a personal (unmanaged) Teams account, your admin needs to have that specific setting turned on as well.
Add a Guest to a Team
If you need someone outside your organization to participate in a team’s channels, view shared files, and collaborate on an ongoing basis, you can add them as a guest. Only team owners can do this, and guest access must be enabled by your IT admin. If you try to add a guest and see a “We didn’t find any matches” error, your organization doesn’t allow guests.
On desktop, hover over the team name in your sidebar and select More options (the three dots), then Add member. Enter the guest’s email address. Anyone with a business or consumer email account, including Outlook, Gmail, or other providers, can join as a guest. After typing the address, select it to confirm, then click “Add (name) as a guest?” and select Add.
On mobile, go to the team in your team list, tap More options, then Manage members. Tap Add members, enter the guest’s email address, tap Invite as a guest, and then tap the checkmark to confirm.
The guest will receive a welcome email with instructions on how to join. It can take a few hours after you add them before they actually have access, and they won’t see the team until they accept the email invitation. Their profile card in your team will only show their name. If you need to add other details like a phone number or title, your IT admin has to handle that.
What Your Admin Needs to Enable
Both methods depend on admin-level settings. External access in Teams has two layers: organization-wide settings that apply to everyone, and user-level policies that control which specific people in your company can communicate externally. Both layers need to allow it for you to reach outside contacts.
Admins manage these settings in the Teams admin center under Users, then External access. By default, all external domains are allowed, meaning your organization can communicate with any other Teams organization. But admins can restrict this in several ways:
- Allow only specific domains: Only email addresses from approved domains will work for external chat and meetings.
- Block specific domains: All domains are allowed except those on a blocklist.
- Block all external domains: No one in your organization can find, call, chat, or meet with anyone outside the org.
- Block specific users: Individual external email addresses can be blocked while the rest of a domain remains open.
For people using personal Teams accounts (not tied to any organization), there’s a separate toggle. The admin needs to turn on “People in my organization can communicate with unmanaged Teams accounts.” There’s also an optional checkbox to let those unmanaged users initiate conversations first.
If you’re trying to add an external contact and it isn’t working, the most likely cause is one of these settings. Check with your IT admin to confirm that external access or guest access is turned on for your account.
Chat vs. Guest Access
Starting a chat with an external contact gives you a simple messaging channel. You can exchange messages, share files within the chat, and make calls. But the external person won’t see your team’s channels, shared documents, or any other team resources.
Adding someone as a guest gives them much broader access. They can participate in channel conversations, view and edit shared files, and join meetings tied to that team. This makes guest access the better choice for vendors, clients, or collaborators who need to work alongside your team over weeks or months. For a quick question or occasional check-in, a direct chat is simpler and doesn’t require team-owner permissions.