How to Port Your Business Phone Number to Teams (Calling Plans)

By Justin N. · Updated 2026-10-22 · This page may contain affiliate links

Your main number is printed on the van, the website, and every invoice, so moving it to Teams has to go right the first time. If you use a Microsoft Calling Plan, Microsoft runs the port through a wizard in the Teams admin center. Most rejected ports come down to the paperwork not matching what your current carrier has on file. Here's what to gather, how to submit, and how to time the cutover.

Who this is for: a small business moving existing numbers from its current carrier to a Microsoft Teams Calling Plan. If you chose an Operator Connect carrier, it handles porting itself: Microsoft lists porting support as something to compare between operators (Plan for Operator Connect). Everything below was checked against Microsoft Learn on 2026-10-22.

Before you start

Licenses first. Have Teams Phone and a Calling Plan in place (see Teams Phone licensing).
Admin role. Microsoft says to use the Teams admin center with the Teams Telephony Administrator, Teams Communications Administrator, or Teams Administrator role (Transfer phone numbers to Teams).
Check what can't move. Microsoft says you can't transfer numbers used for data connections like DSL or broadband, Universal International Freephone Numbers, or numbers dedicated to faxing. Fax numbers can be ported, but fax service won't keep working, because Phone System and Calling Plan licenses don't include faxing. Microsoft also notes that porting mobile numbers to a Calling Plan is only available in the United States, Puerto Rico, and Canada (Port order overview).
Don't cancel your old service yet. Microsoft says that once the port completes, Microsoft becomes your provider and you can disconnect the old service. Keep the old account active and paid until then.

What to gather from your current carrier

Microsoft says each port order must have all numbers on the same account number, billing telephone number (BTN), service address, and business name, and must come from one carrier (Port order overview). Get these exactly as the carrier has them:

Account number, from a bill or the carrier's portal.
Billing telephone number (BTN), the main number on the account. Microsoft says a BTN that doesn't match is a reason for rejection.
Business name and service address, which can differ from the billing address.
Authorized user, someone your carrier has on file as authorized on the account.
Account PIN, if the account has one. Microsoft says it's required for all mobile numbers.
The carrier's record of your account. In the U.S. that's the Customer Service Record (CSR). Asking for it is the easiest way to confirm the details above.

Remove any port freeze. Microsoft says some carriers put accounts on a "freeze" to block unauthorized ports, that a frozen account gets the port rejected, and that removing a freeze can take one to three weeks depending on the provider (Port order overview). Ask your carrier first.

Full port or partial port?

Microsoft says a full port moves every number on the BTN, including the BTN itself, and closes the account with your current carrier. A partial port moves only the numbers you list. In a partial port that includes the BTN, you can name a number that stays behind as the new BTN (Transfer phone numbers to Teams). If the internet line or an alarm line is on the same account, a partial port keeps them with the old carrier.

Submit the port order

In the Teams admin center, go to Voice > Phone numbers, select Numbers, then Port. For U.S. and Canadian numbers, Microsoft offers a newer US & Canada wizard alongside the classic one.
Choose the country your numbers are in. Microsoft says the wizard then lists the documents you'll need from your current carrier.
Add the numbers, either typed in (10-digit or E.164 format, no ranges) or as a one-column CSV with a PhoneNumber header. If the wizard groups your numbers by account, carrier, or type, each group needs its own port request.
Enter the BTN, account details, and authorized user exactly as your carrier has them. You can save and come back later under Voice > Phone numbers > Order history.
Pick a target date, then submit.

Steps from Transfer phone numbers to Teams. Country-specific Letter of Authorization (LOA) forms are linked from the same page.

Timing the cutover

Microsoft says the U.S. needs at least a five-day lead time and Canada at least ten. You can't pick a date more than 30 calendar days out, and processing typically takes 7–14 days from start to finish (Port order overview).
Microsoft calls a date under seven business days away (U.S.) an "aggressive" target. That's fast if everything is right, but less predictable. For a main line, I'd pick a conservative date on a quiet weekday morning.
Your old carrier answers with a firm order commitment (FOC) date. On that date, Microsoft says, the old carrier releases the numbers and Microsoft points them at your tenant.
Build the auto attendant and call queues before the port date, so the main number has somewhere to go the moment it arrives.

After the port

Assign the numbers: user numbers under Voice > Phone numbers (select a number, Edit, assign it to a user, and set the emergency location), and the main number on the auto attendant's resource account (Assign phone numbers).
Call every ported number from a mobile.
Only then cancel any leftover service with the old carrier, if it was a partial port.

More in the Teams Phone series: Calling Plan vs Operator Connect vs Direct Routing · Teams Phone licensing with Business Premium or E3 · Auto attendant and call queue setup · Teams call quality basics · Teams-certified headsets and desk phones. Choosing a Microsoft 365 plan first? See Business Premium vs E3.

Sources

Useful links for this guide: Microsoft's port order overview and the LOA forms by country. These are ordinary links, not affiliate links.

Accuracy note: Microsoft changes admin center menus and licensing often. Paths and prices were checked against Microsoft documentation on 2026-10-22. If something has moved, tell me at [email protected].