Number Porting: What Actually Happens, and Why It Fails

The single biggest obstacle to changing phone providers is not price or features. It is the fear of losing the number on your business cards, your vehicles, your signage and every directory listing going back a decade.

That fear is reasonable and mostly misplaced. Porting is a regulated, routine process. But it has specific failure modes, and nearly all of them are avoidable with information you can gather in an afternoon.

What a port actually is

Your phone number is not owned by your carrier. It is assigned to you, and the carrier currently providing service for it is the losing carrier. The provider you are moving to is the gaining carrier.

A port is a request from the gaining carrier to take over routing for that number, validated against the losing carrier's records. When it completes, calls to that number route to your new service. The number is unchanged, and callers notice nothing.

In the US this runs through a shared industry process with defined timelines. Your provider handles the mechanics; your job is supplying accurate information and choosing when it happens.

The stages, and realistic timing

1. Collect your details. You need a recent bill from the losing carrier, the exact account name and number, the service address as the carrier holds it, and the full list of numbers to move.

2. Letter of Authorization (LOA). A signed document authorising the gaining carrier to act for you. It must be signed by someone the losing carrier recognises as authorised on the account.

3. Submission and validation. The gaining carrier submits the request. The losing carrier validates it against their records and either accepts or rejects it, typically within 24–72 hours for simple accounts.

4. Firm Order Commitment (FOC). On acceptance you get a scheduled date and time. Simple business ports commonly land about 7–14 business days from submission; complex ones — many numbers, multiple locations, or a legacy circuit — take longer.

5. The cutover. On the FOC date, routing switches. The window is usually minutes, and should be scheduled outside business hours.

6. Post-port cleanup. Cancel the old service after confirming the port completed. Do not cancel before — see below.

Plan for three to four weeks end to end for a straightforward business port. Anyone promising 48 hours for a multi-line account is describing an exception, not a plan.

The five reasons ports get rejected

Nearly every rejection is one of these, and all five are preventable.

1. Account details do not match exactly

The commonest by far. The port request must match the losing carrier's records character for character — not what you call the business, what their billing system holds. "ACME Corp" against "Acme Corporation, Inc." is a rejection. So is a suite number present in one record and missing in the other.

Prevention: copy the details from a recent bill, not from memory. If in doubt, ask the losing carrier for a Customer Service Record (CSR), which shows exactly what they hold.

2. The account has a pending order

A port cannot proceed while another change is in flight — a plan change, an address update, a feature addition, or another port.

Prevention: make no changes to the old account from the moment you decide to move.

3. The service was cancelled first

This is the one that causes real damage. Cancel service and the number is released; once released, it can be reassigned and may be unrecoverable. There is no undo.

Prevention: never cancel until the port has completed and you have confirmed calls are arriving on the new service.

4. The authorised signatory is wrong

The LOA must be signed by someone listed on the account. A new office manager who is not on the record will be rejected regardless of their actual authority.

Prevention: check who the carrier has on file before preparing the LOA, and update it first if needed.

5. The number is not portable to that location

Portability has geographic limits. Some numbers — certain toll-free vanity arrangements, some numbers tied to specific rate centres — have constraints. Occasionally a number simply cannot move to the requested service area.

Prevention: ask the gaining carrier to run a portability check on the full list before you commit to anything.

Partial ports, and why they are useful

You do not have to move everything at once. Porting the main line while leaving others in place is common, and it reduces risk considerably: move a small group first, confirm everything works, then move the rest.

The caveat is that splitting numbers across two providers can complicate caller ID and outbound routing while both are live. Keep the split period short and deliberate.

What good looks like on the day

• The cutover is scheduled outside business hours, with a named person on both sides.
• Call forwarding is configured on the new service before the port, so routing is correct the moment it completes.
• A test call to every ported number from an outside line, immediately after.
• The old service stays active for a few days as a safety net, then is cancelled on confirmation.
• Directory listings, Google Business Profile, invoices and website updated — the number has not changed, but confirm nothing references a temporary number used during migration.

Questions to ask any provider

• Is porting included, or is there a per-number charge?
• Will you run a portability check on the full list before I sign anything?
• Who prepares the LOA, and who chases a rejection?
• What is your realistic FOC window for an account this size?
• What happens to my service if the port is rejected?
• Can we port in batches?

The answers tell you a great deal about how the rest of the relationship will go. A provider who treats porting as your problem has told you something useful before you have bought anything.