What to expect, exactly.

Mail, calendars and personal contacts all move together.

Inbox rules are rewritten to point at the folders they moved to, so they keep working rather than quietly failing against a folder that no longer exists. Out-of-office replies come across as well.

Shared, resource and archive mailboxes each count as one unit, at the same rate as a person’s mailbox.

Each person’s own files move with their version history and their original dates intact — not a flat copy of the current version stamped with the date of the migration.

Deleted items can be migrated too, where you want the destination to match the source exactly rather than only its live content.

One-to-one and group chats move with their original authors, and in their original order.

They do NOT keep their original dates, and this is the one worth understanding before you start. Microsoft does not allow a chat message to be created backdated by anyone, so conversations arrive in the right order carrying the time they were migrated rather than the time they were sent.

Because of that, a transcript of each conversation is written to the person’s OneDrive. That transcript is where the true chronology survives, with every message and its real timestamp.

Document libraries are chosen one at a time, and move with their version history and source timestamps.

Permissions and sharing links are reported rather than copied. That is deliberate: a new tenant is better designed than inherited, and the report is what you design from. It names every grant and every link so nothing is lost — it just does not recreate them for you.

You can design the destination structure ahead of the move — the libraries and folders you want, rather than the ones you have.

Messages arrive as messages — original authors, original dates, replies still threaded — including from people who have already left and have no account at the destination.

Standard channels take their history directly. Private and shared channels cannot: Microsoft does not permit message history to be written into them by anyone, by any tool. Those arrive as a readable archive in the channel’s own Files tab, where exactly its members can open it.

The usual alternative is leaving that history behind entirely.

The Files tab is a SharePoint library rather than part of the conversation, so bringing it is a tick box on the Teams form — on by default. It creates a SharePoint migration for the team’s site once the destination team exists, charged per GB, and that migration waits for you to approve its size before it moves anything.