How to Port Your Phone Number to VoIP: Step-by-Step Guide for 2025

Your business phone number is more than a string of digits — it is on your website, business cards, Google listing, and in the contact books of every customer you have ever served. When switching to VoIP, keeping that number is non-negotiable. The good news: number porting is a federally protected right under Local Number Portability (LNP) rules enforced by the FCC. Every carrier is required to release your number when you request a port. This guide walks you through the entire process so you can switch to VoIP without losing a single call.

Number porting is the process of transferring a phone number from one service provider to another. When you port your number to a VoIP provider, the routing instructions in the national phone number database are updated so that calls to your number are delivered to your new VoIP system instead of your old carrier. The process is governed by FCC regulations and involves coordination between your current carrier (the "losing carrier") and your new VoIP provider (the "gaining carrier"). Your VoIP provider handles most of the work — you just need to supply accurate account information and authorize the transfer.

Gather the following before submitting a port request: 1. A recent phone bill from your current carrier — this confirms your account number, name, and service address. 2. The exact account holder name as it appears on the bill. 3. Your account number and any PIN or passcode associated with the account. 4. The service address on file with your current carrier. 5. A list of all phone numbers you want to port. Double-check every detail against your bill. Even a small mismatch — an abbreviated street name, a missing suite number, or an old name on the account — can cause the port to be rejected and add days to the timeline.

Before committing to a port, ask your new VoIP provider to run a portability check. They will query the national database to confirm that your number can be ported and identify which carrier currently controls it. This check is free and takes seconds. If there is an issue — such as the number being on a carrier that does not support porting electronically — your provider will let you know upfront and suggest alternatives.

Your VoIP provider will supply a Letter of Authorization (LOA) form. This document authorizes them to submit the port request on your behalf. Fill out the LOA carefully: • Account holder name — must match your current carrier records exactly. • Account number — copy from your latest bill. • Phone numbers to port — list every number, including any fax lines or secondary numbers. • Authorized signature — the account holder or an authorized company representative must sign. Many providers accept electronic signatures, so you can often complete this step in minutes through an online portal.

Once the LOA is signed, your VoIP provider submits the port request to your current carrier through an automated system called the Local Service Management System (LSMS). The current carrier has a set timeframe to respond: • Simple ports (1–5 lines at a single location): response within 1 business day. • Complex ports (multiple locations, large blocks of numbers): response within 3–5 business days. If the carrier finds an error (mismatched name, wrong account number), they will issue a rejection with a reason code. Your VoIP provider will contact you to correct the information and resubmit.

After the losing carrier accepts the port request, they issue a Firm Order Commitment (FOC) date. This is the scheduled date and time when the number will officially transfer to your new VoIP provider. During the waiting period: • Keep your current phone service active — do not call to cancel. • Set up your VoIP system: configure extensions, auto-attendants, voicemail, and ring groups. • Test inbound and outbound calling using a temporary number from your VoIP provider. This preparation ensures your team is ready the moment the port goes live.

On the FOC date, the number database is updated and calls begin routing to your VoIP system. The cutover typically happens within a few minutes, though it can take up to an hour for all carrier networks to propagate the change. What to do immediately after the port completes: • Place a test call to your ported number from an outside line. • Verify caller ID displays your company name correctly. • Test voicemail, call forwarding, and any auto-attendant greetings. • Confirm that your old carrier account shows the line as disconnected. Once everything checks out, your migration is complete. Your old carrier will send a final bill for any remaining charges.

The most frequent issues that delay or derail a port: Mismatched account information: The name, address, or account number on your LOA does not match your carrier records. Always copy details from a recent bill exactly as printed. Account has a freeze or hold: Some carriers place a "port freeze" on accounts to prevent unauthorized transfers. Contact your current carrier to remove any freeze before submitting the port request. Pending orders on the account: If there are any open service change orders on your current account, the port may be blocked. Ask your carrier to close pending orders first. Disconnected number: If you cancel your old service before the port completes, the number may be released. Never cancel until the port is confirmed. Partial ports: If you are porting some but not all numbers on an account, make sure the remaining numbers are on a separate billing group to avoid disruption.

Here is a realistic timeline for a typical business number port: Day 1: Sign up with new VoIP provider, run portability check, sign LOA. Day 2–3: VoIP provider submits port request; current carrier responds. Day 3–5: If rejected, correct information and resubmit. Day 5–10: Waiting period after FOC is issued. Day 10–14: Port goes live; calls route to your VoIP system. Wireless number ports tend to be faster (1–3 business days), while large enterprise ports with hundreds of numbers may take 30+ business days and require a dedicated project manager.

Number porting is a routine process that VoIP providers handle every day. The key to a smooth transition is accurate paperwork, keeping your old service active until the port completes, and having your new VoIP system configured and tested in advance. ON VoIP manages the entire porting process for you — from portability checks to LOA submission to go-live verification. Our onboarding team tracks every port request and proactively resolves any issues so your business never misses a call.