Add a Guest to Slack or Teams (and What Guests Can Actually Do)

The quick version

In Slack, guests exist only on paid plans: a Workspace Owner or Admin invites them, picks their channel or channels, and can set an automatic deactivation date. In Teams, any team owner can add a guest with any email address, but only after an admin has enabled guest access for the organization. In both apps the guest is clearly labeled and sees less than a member.

What "guest" means in each app

A Slack guest belongs to your workspace: your company pays for multi-channel guests as if they were members, and you choose exactly which channels they can see. Slack itself suggests Slack Connect instead when the other person already uses Slack at their own company, so each side keeps its own workspace. A Teams guest is a Microsoft Entra B2B account: Microsoft creates a guest identity in your directory, covered by the same compliance and auditing as your own users, and it works with all Microsoft 365 Business Standard, Enterprise and Education subscriptions with no extra license. If you only need to chat and call with people at another Microsoft 365 organization, Microsoft points you to external access instead of guests.

Slack: invite a guest

On desktop, click your workspace name in the sidebar, select Invite people, and enter the guest's email address. Workspace Owners and Admins get a drop-down to choose members or guests; pick guests, choose the channel or channels they will be added to, optionally set a time limit on the account, and click Send. Members cannot invite guests directly, but they can submit a request for an admin to approve. Invitations stay active for 30 days, and owners and admins can resend a pending one. Two catches from Slack's help pages: you cannot invite guests from Slack's mobile apps at all, and owners and admins can also convert an existing member into a guest from the same settings area.

Slack: single-channel, multi-channel, and the bill

Multi-Channel Guests are billed as regular members and can be added to as many channels as you specify. Single-Channel Guests are free, limited to one channel, and you get up to five of them for every paid active member in your workspace. If you set an automatic deactivation, the guest and the admin who set the date get a reminder five days before it hits, and the admin can extend it. Spot the difference at a glance: multi-channel guests show a square shape next to their names, single-channel guests a triangle.

Teams: admin first, then the team owner

Guest access is an organization-wide setting that an admin must enable before anyone can invite. Once it is on, a team owner hovers over the team name, selects More options, then Add member, enters the guest's email (Outlook, Gmail, anything), selects it to confirm, adds the guest's name and selects Add. Do the name step right away: Microsoft's help warns that changing it later takes an IT admin. The guest receives a welcome email and must accept the invitation before they can get in, and Microsoft says access can take up to 12 hours. If you see "We didn't find any matches" while adding someone, your organization does not allow guests, so that is an admin conversation, not a typo.

What guests can and can't do

Teams guests can do more than most people expect: per Microsoft's capabilities table they can participate in channel conversations and private chats, share channel files, edit and delete their own messages, and even create channels. They cannot share files in a chat, add apps, create a team, discover and join public teams, or view the org chart, and their name always carries a (Guest) label. Slack guests sit tighter: they see only the channels you picked, they cannot create public channels, rename, archive or delete channels, remove members, or install apps, and a single-channel guest's world is one channel. In both apps a departing guest can leave on their own, but Microsoft notes that leaving a team does not delete the guest account from your directory; an admin has to remove it.

Which door to use

Our rule of thumb: if the person will live in your channels daily, a guest account is the right door, single-channel in Slack when one channel covers it because it is free. If they already run their own Slack workspace or Microsoft 365 tenant, use Slack Connect or Teams external access or shared channels instead, so nobody pays for a duplicate seat and both sides keep their own home. Whatever you pick, set the deactivation date when you invite them; the five-day reminder Slack sends is only useful if a date exists. If guest chat is where your shared emojis will live, our custom emoji guide covers adding them once you are set up.

What to be careful about

• Slack guests cost money except the single-channel kind. Multi-channel guests bill like members; single-channel guests are free, five per paid member.
• Guests cannot be invited from Slack's mobile apps. Use the desktop app or browser.
• Teams guest access is off until an admin enables it. "We didn't find any matches" means the organization blocks guests.
• Name the Teams guest at invite time. Fixing the name afterward requires an IT admin.
• Access is not instant in Teams. Microsoft says it can take up to 12 hours after the guest accepts.
• Leaving is not deleting. A Teams guest who leaves the team still has a guest account in your directory until an admin removes it.

Sources

Checked October 19, 2026. The steps, billing and limits follow each product's own help articles. The which-door-to-use advice is ours.

• Slack: Understand guest roles in Slack
• Slack: Invite new members to your workspace
• Microsoft Learn: Guest access in Microsoft Teams
• Microsoft Support: Add guests to a team
• Microsoft Support: Team owner, member, and guest capabilities