Number Portability: How to Port Your Numbers

Switching carriers does not mean giving up your phone numbers. FCC regulations guarantee your right to keep your numbers when you move to another provider serving the same area — a right called number portability, exercised through a process called number porting. This guarantee exists because without it, carriers could hold your phone numbers hostage — keep paying us or lose the numbers your customers know. The FCC eliminated that leverage through Local Number Portability (LNP) rules that have been in effect since the late 1990s.

Despite the regulatory guarantee, porting is the process operators dread most when switching carriers. Not because it is technically complex — it is straightforward — but because it involves coordination between your old carrier (who may not be eager to see you leave), your new carrier (who needs to execute the port correctly), and a national database system that must update routing for every ported number. When any step in this chain goes wrong, the port is delayed. Understanding the process helps you avoid the common mistakes that cause delays.

SIPNEX is an FCC-licensed carrier. When you port numbers to us, we manage the port submission, FOC coordination, and cutover on your behalf. This guide explains how the process works so you know what to expect.

What number portability (LNP) is

Number portability (formally Local Number Portability or LNP) is your right to keep a phone number when changing carriers; number porting is the process that exercises it — moving a number from one carrier (the “losing carrier” or “old carrier”) to another carrier (the “gaining carrier” or “new carrier”). After the port completes, calls to that number are routed to the new carrier’s network instead of the old carrier’s network. The number itself does not change — only the carrier behind it changes.

Porting is managed through the NPAC (Number Portability Administration Center), the national database that maintains the routing information for all ported US numbers. When a number is ported, its NPAC record is updated to map the number to an LRN on the gaining carrier’s network. Every carrier in the telephone network queries this data (directly or indirectly) to determine where to route calls for ported numbers.

Portability has a geographic limit: it moves a number between providers, not between places. The gaining carrier has to be able to serve the number’s rate center — the local exchange area the number is assigned to. The FCC’s consumer guide to porting frames the right as keeping your number when you switch providers and stay in the same geographic area, and notes that some rural wireline carriers hold state waivers from the porting requirement. Check that the gaining carrier covers each number’s rate center before you sign an LOA.

The porting process step by step

Step 1: Gather your current account information. Before initiating a port, you need: the authorized name on your current carrier account (must match exactly), your account number with the current carrier, your account PIN or passcode (if your carrier uses one), the billing address on the account, and the phone numbers you want to port. This information must match your current carrier’s records exactly — a character mismatch on the authorized name or a wrong account number will cause a rejection.

Step 2: Submit a Letter of Authorization (LOA). The LOA is a document that authorizes the gaining carrier to port your numbers. It includes your name and business name, the phone numbers to port, your current carrier’s account information, and your signature (electronic or physical). SIPNEX provides a standardized LOA form — you fill in the details and sign it. We submit it as part of the port request.

Step 3: The gaining carrier submits the port request. SIPNEX generates a Local Service Request (LSR) — the industry-standard carrier-to-carrier order form — and submits it to the losing carrier. The LSR identifies the numbers being ported, the gaining carrier (SIPNEX), and the account details taken from your LOA.

Step 4: The losing carrier reviews and confirms. The losing carrier receives the LSR and has a defined window to review it. They verify that the information matches their records. If everything matches, they confirm the port and a FOC (Firm Order Commitment) date is set — this is the date the port will execute. If information does not match, they reject the port with a reason code, and you need to correct the LOA and resubmit.

Step 5: FOC date — the port executes. On the FOC date, the NPAC database is updated to route calls for your numbers to SIPNEX’s network. Your numbers are now live on SIPNEX. Calls to those numbers arrive at your SIP trunk endpoint. Outbound calls presenting those numbers are signed with SIPNEX STIR/SHAKEN attestation.

Step 6: Verification and old carrier cancellation. After the port completes, verify that inbound calls route correctly and that outbound CID works. Once confirmed, the old carrier’s service for those numbers terminates automatically (the numbers are no longer on their network). Your old carrier may continue billing for the month depending on their billing cycle — review your final invoice.

Timelines

You may have read that the FCC requires ports to complete in one business day. The one-business-day standard (FCC Order 09-41, May 2009) is real, but it governs one narrow thing: how fast a complete, accurate request for an FCC-defined “simple port” must be completed — a single-line account with no unbundled network elements, no complex switch translations such as Centrex or ISDN, and no reseller involved. Most multi-number business ports fall outside that definition.

End to end — gathering account information, executing the LOA, preparing and validating the LSR, working through any rejection-and-resubmission cycles, and scheduling the FOC date — realistic timelines look like this:

Standard business ports (1-10 local numbers from one carrier): 7 to 14 business days from LOA submission to FOC date. This is the typical timeline for most business ports.

Complex ports (large blocks or multiple losing carriers): 14 to 21 business days or more. Ports involving hundreds of numbers, multiple losing carriers, or numbers that require coordination across different systems take longer.

Toll-free number ports: Toll-free numbers use a different process — RespOrg transfer through the Somos Toll-Free Number Registry (formerly SMS/800) rather than LNP through the NPAC. Timeline: 5 to 15 business days depending on the current RespOrg’s cooperation.

Wireless to VoIP ports: Porting a cell phone number to a VoIP carrier follows the standard LNP process, provided the gaining carrier can serve the number’s rate center. Being wireless does not by itself make a port slow — the FCC’s consumer guide notes that moves between wireless providers can complete within a few hours. The usual snag is paperwork: the major mobile carriers generally require a number transfer PIN, generated on the losing account, along with the account number.

Does porting cost anything?

Sometimes. The FCC’s consumer porting guide says companies may charge a fee to port your number, and suggests asking whether the fee can be waived or negotiated. The same guide says the losing carrier cannot refuse to port your number because you owe an outstanding balance or an early-termination fee — though you still owe that money after the port completes.

SIPNEX’s published pricing lists no port-in or port-out fees for US numbers. The costs to watch are on the losing carrier’s side — final-cycle billing on the old account and any early-termination clause in your existing contract.

Common causes of port delays

Mismatched account information. A leading cause of port rejections. The authorized name on the LOA must match the name on the losing carrier’s account exactly. “John Smith” does not match “John R. Smith.” “ABC Company LLC” does not match “ABC Company.” Before submitting your LOA, call your current carrier and confirm the exact name, account number, and PIN on file. Write it down character by character.

Account has pending orders. If there is an active order on your current carrier account (a feature change, an upgrade, a pending disconnect), some carriers will reject the port until the pending order clears. Resolve any open orders before initiating the port.

Partial port confusion. If you are porting some but not all numbers from your current account, the losing carrier must process a partial port. Some carriers handle partial ports smoothly. Others struggle with them. If possible, port all numbers from an account simultaneously to avoid partial-port complications.

BTN (Billing Telephone Number) conflict. If the number you are porting is the BTN (primary billing number) on the account and other numbers remain, the losing carrier must assign a new BTN to the account before releasing the ported number. This adds a step and can delay the port. Solution: if you are porting the BTN, tell your current carrier in advance so they can reassign it.

Losing carrier delays. Some carriers process port requests slowly — either due to operational inefficiency or as a retention tactic (making it painful to leave). While the FCC has rules about timely port processing, enforcement is imperfect. If your port is delayed beyond reasonable timelines, SIPNEX can escalate with the losing carrier and, if necessary, help you prepare an FCC informal complaint.

During the port: no service interruption

A properly executed port has zero service interruption. Here is why:

Your numbers remain active on the losing carrier until the FOC date. On the FOC date, the NPAC record is updated and calls begin routing to SIPNEX. The cutover happens at the network routing level — there is no physical disconnection and reconnection. One moment your number routes to the old carrier; the next moment it routes to SIPNEX. If you have already completed your SIP trunk configuration and tested with new SIPNEX DIDs, the ported numbers light up on your system the moment the routing switches.

The parallel operation strategy: While the port processes, you can immediately start using new SIPNEX DIDs for outbound calling. Your campaigns continue on new numbers while your established numbers port in the background. When the port completes, add the ported numbers to your CID rotation and inbound routing. This ensures zero downtime — you are operational on SIPNEX from day one, and your ported numbers join the existing configuration when they arrive.

After the port

CNAM registration. Ported numbers may retain the old carrier’s CNAM record. SIPNEX re-registers CNAM as part of the post-port process. Allow 24 to 72 hours for propagation.

STIR/SHAKEN verification. Ported numbers are added to your SIPNEX STIR/SHAKEN authorized CID list upon port completion. Outbound calls using ported numbers receive A-level attestation immediately.

Caller ID reputation. Your ported numbers carry their existing reputation history. If the numbers had good reputation on the old carrier, they retain it. If they were flagged, the flag follows the number — CNAM and attestation improvements will help, but reputation remediation may be needed.

Old carrier final billing. Review your final invoice from the losing carrier. Confirm that billing stops for the ported numbers. Some carriers continue billing until the end of the billing cycle. Dispute any charges after the port completion date for ported numbers.

Frequently asked questions

How long does number porting take?

Standard business ports (1-10 local numbers from one carrier): 7 to 14 business days. Complex ports (large blocks or multiple losing carriers): 14 to 21 business days or more. Toll-free numbers: 5 to 15 business days via RespOrg transfer. The timeline starts when the gaining carrier submits the port request with a complete, accurate LOA. Delays usually come from mismatched account information on the LOA, which triggers a rejection and resubmission cycle. Verify your account details with your current carrier before submitting the LOA to minimize the risk of rejection.

Will I lose service during the port?

No, if the port is executed correctly. Your numbers remain active on the losing carrier until the FOC (Firm Order Commitment) date. On the FOC date, routing switches to the gaining carrier at the network database level — no physical disconnection. If your new carrier’s trunk is configured and tested in advance, the ported numbers are immediately functional on your new system. There is no gap. The key is preparation: have your new trunk configured and tested with new DIDs before the port completes, so the ported numbers simply join an already-working system.

Can my current carrier block the port?

Your current carrier cannot refuse to release your numbers — FCC regulations prohibit carriers from blocking valid port requests. They can reject a port request for specific valid reasons (mismatched account information, incomplete LOA, pending orders on the account), but these are procedural rejections that can be resolved by correcting the information and resubmitting. If your carrier delays or obstructs a valid port beyond reasonable timelines, you can file an informal complaint with the FCC. In practice, most carriers process ports within the standard timeframes, though some may be slower than others.

Do I need to cancel service with my old carrier after porting?

For the ported numbers specifically, no — the port automatically terminates service for those numbers on the losing carrier. However, if you have other services on the account (remaining numbers, internet, bundled services), those continue. You may need to explicitly cancel the account or remaining services to stop billing. Review your final invoice to confirm that ported numbers are no longer being charged. If you ported all numbers from the account, the account should close automatically, but confirm with the losing carrier to avoid surprise charges.

Can I port numbers from any carrier to SIPNEX?

In most cases, yes. FCC number portability rules cover landline, wireless, cable, CLEC, and interconnected VoIP providers, and the process is the same regardless of the losing carrier type. The real limit is geography: the gaining carrier has to be able to serve each number’s rate center, so confirm coverage for every number before you sign the LOA. Documentation also varies — the major mobile carriers generally require a number transfer PIN, and some carriers add other verification steps. Toll-free numbers use the RespOrg transfer process instead of LNP, but the result is the same — your numbers move to SIPNEX.

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SIPNEX handles number porting as part of trunk provisioning — we manage the LOA submission, FOC coordination, and cutover, and ported numbers arrive with A-level STIR/SHAKEN attestation and CNAM registration set up. Start a port request.