Link SharePoint Online users with Active Directory

Question

New here, and looking for some information. I've searched but don't see anything directly related.

We have a small international affiliate that is wanting to use SharePoint Online rather than our main SP instance for various reasons including data sovereignty. They have only about 25 users, and I'm considering setting them up with authentication in SP online itself, rather than syncing the Active Directory just for that small number of users (They have AD accounts but their work machines are not part of the domain and they access network resources via terminal server).

What I'm wanting to clarify is what the deal is if we want to bring in the AD sync further down the line. Is there any way in SharePoint Online to indicate in the account settings the AD username to which it should be linked? Does it rely on email address or something else? The last thing I would want would be to hook up the AD sync and have it duplicate users.

Thanks for any advice or insight.

Answer 1

Just coming back to this, and my answer was that yes, the AD sync will tie up users if the email addresses match. Turns out we had some users in the SP Online user set already and simply matching the email addresses sorted us out when we enabled AD sync.