Keeping your existing numbers is usually the thing that stops businesses from switching providers, and it is almost always an unfounded fear. Local number portability is a regulated process with defined steps. Ports go wrong for boring, preventable reasons.

How it works

You are the customer, but the process runs between carriers.

  1. You sign a Letter of Authorization (LOA) giving the new provider permission to request your numbers.
  2. Your new provider submits a port request to your current carrier with your account details.
  3. The current carrier validates it against their records, and either rejects it or returns a Firm Order Commitment (FOC) date.
  4. On the FOC date, at a scheduled time, the numbers cut over.

The critical detail: do not cancel your existing service before the port completes. Cancelling releases the numbers, and a released number cannot be ported. It is the single most expensive mistake in this process and it is irreversible.

Why ports get rejected

Nearly every rejection traces to a mismatch between what you submitted and what your current carrier has on file.

Name or address mismatch. The service address on file, not your billing address or your current office. If you moved and never updated the carrier, submit the old address.

Account number or PIN wrong. Many carriers require a porting PIN separate from your account password. Get it before you start.

Numbers not on the account. Numbers billed separately, or sitting on a different account than you assumed.

Pending account changes. An open order, a recent plan change, or an unpaid balance can block a port.

The fix is to pull a Customer Service Record (CSR) from your current carrier first. It lists exactly what they have: account name, service address, and every number on the account. Submitting from the CSR rather than from memory eliminates most rejections.

Timelines

Simple ports of a few numbers typically take one to two weeks from clean submission to FOC date. Larger or more complex ports, especially those involving PRIs or numbers spread across accounts, take three to four weeks.

Each rejection restarts the clock, which is why getting the paperwork right the first time matters more than anything else in the process.

Partial ports and the trap inside them

You can port some numbers and leave others. Be careful with the main billing telephone number: on many accounts it anchors the others, and porting it away can cancel the remaining service, taking numbers you meant to keep.

If you are porting in stages, tell your provider which number is the BTN and plan the sequence deliberately.

Cutover day

A well-planned port is uneventful. To keep it that way:

  • Have the new system fully configured and tested with temporary numbers before the FOC date, so the only change on the day is which numbers point at it
  • Schedule cutover for a low-volume window, typically early morning
  • Keep the old system running for a few days afterward
  • Test inbound from an external mobile immediately after cutover, on every ported number
  • Confirm outbound caller ID displays correctly, which is a frequent post-port oversight
  • Re-register E911 addresses for ported numbers; they do not carry over

After the port

Verify a full billing cycle on the old account to confirm it closed properly. Update the number everywhere it is published: website, Google Business Profile, invoices, email signatures, directory listings. The number has not changed, but its listings may reference call tracking that has.

Then cancel the old service, once, and only once every number has been confirmed working on the new one.