What Does Porting a Number Mean? Port In, Port Out and How Long It Takes
Porting a number means moving your phone number from one provider to another so you keep it. Here is what port in and port out mean, how long it takes in the US and UK, and how to start.
Porting a number means moving your phone number from one provider to another so you keep it. A "port in" is the number arriving at your new provider; a "port out" is the number leaving your old one. US rules allow one business day for simple landline and VoIP ports; UK mobile switches take one working day.
Quick answer
You ask your new provider to bring your number across. The new provider sends a port request to your old provider using details from your old account, and the number moves over. Your service with the old provider for that number then ends. Last checked 22 October 2026.
What does "port in" mean?
"Port in" means your number is being transferred into a new provider's network from another provider. The new provider requests the port from your old provider using details from your old account, such as the account number and the name and address on the account. In the US, the old carrier can ask only for a fixed set of details for a simple port (47 CFR 52.36).
What does "port-in required" mean?
On a new line, it usually means the line will use a number you are bringing from another provider, so the setup is not finished until the port completes. Ask your new provider exactly what it needs to finish the port.
What does "port out" mean?
"Port out" means your number is leaving your current provider for another one. The FCC describes a number being "transferred (or 'ported out')" to an account with a new provider. Under rules adopted in November 2023, US wireless providers must notify customers immediately when a port-out request is made on their account, and must offer an account lock that blocks ports (FCC 23-95).
How long does porting take?
- US landline and VoIP: 47 CFR 52.35 requires a simple wireline-to-wireline or simple "intermodal" port within one business day. Intermodal covers ports between landline and wireless and ports involving interconnected VoIP. Non-simple ports must be completed within four business days, unless the customer or new provider asks for longer.
- UK: your old provider must send your PAC (Porting Authorisation Code) within one minute, the PAC is valid for 30 days, and the new provider must complete the switch within one working day (Ofcom).
How to port your number
- Choose your new provider and check that it can take your number.
- Keep your old service active. Cancelling first can make the port harder.
- Have your old account details ready: account number, account holder's name and address, and any port-out PIN your old provider uses. In the UK, ask your old provider for your PAC code.
- Give these details to your new provider and ask it to start the port.
- Wait for the confirmation. Your number then works with the new provider and the old service for that number ends.
What happens when you port your number?
Your number moves to the new provider, and your service with the old provider for that number ends. In the UK, the old provider must not charge for any notice period after the switching date, though you may still owe an early termination charge if you were in contract, and any loss of service must not last longer than one working day (Ofcom). Ofcom also notes that in most cases you can still move a cancelled number within one month.
Is SIM porting the same as a SIM swap?
No. A SIM swap (SIM change) moves your number to a new SIM with the same provider. A port moves it to a different provider. The FCC's 2023 rules cover both to protect customers' accounts: providers must check who you are before either change and notify you when one is requested (FCC 23-95).
For a new VoIP line at home, see VoIP for home use.
Sources
Checked 22 October 2026: 47 CFR 52.35, porting intervals, FCC 23-95, SIM swap and port-out fraud rules and Ofcom, switching your mobile provider.
Frequently asked questions
What is number porting?
Number porting is moving your existing phone number from one provider to another so you can keep it. You ask the new provider to start the port, and it requests the number from your old provider.
Do I contact my old provider or my new provider to port my number?
Your new provider starts the port. Your old provider only supplies details such as your account number or, in the UK, your PAC code.
How long does it take to port a number?
In the US, simple landline and VoIP ports must be done within one business day and non-simple ports within four. In the UK, a mobile switch must be completed within one working day of the request.
Should I cancel my old service before porting?
No. Keep your old service active until the port is finished, because cancelling first can make the port harder.
Can I port a VoIP number?
Yes. US rules treat ports involving interconnected VoIP as intermodal ports, which have the same one-business-day limit for simple ports. Ask your new VoIP provider to start the port.
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