A transfer needs cooperation from the provider losing the customer. That is why porting has rules, deadlines and an authorization step rather than a button.

## Port, port-out, or forward?

Three different operations, and only two of them move the number.

| Operation  | What happens to the number                      | What you keep paying for                     |
| ---------- | ----------------------------------------------- | -------------------------------------------- |
| Port-in    | It moves to your new provider                   | The new provider only                        |
| Port-out   | It moves away to another provider               | Nothing, once it completes                   |
| Forwarding | It stays where it is, and calls are sent onward | Both the original service and the forwarding |
| New number | Nothing. You take a different number            | The new provider only                        |

Forwarding looks like a port from the outside, because calls reach the right place. It also leaves you paying the provider you were trying to leave.

## How long does a port take?

In the US, one business day for a simple request and four for one that is not.

[47 CFR 52.35](https://www.ecfr.gov/current/title-47/chapter-I/subchapter-B/part-52/subpart-C/section-52.35), the porting-interval rule of the FCC, the US communications regulator, sets the interval and scopes it to simple requests in the same sentence:

> All telecommunications carriers required by the Commission to port telephone numbers must complete a simple wireline-to-wireline or simple intermodal port request within one business day unless a longer period is requested by the new provider or by the customer.

Two qualifications sit alongside it. The rule counts Monday to Friday as business days. It sets 8 a.m. to 5 p.m. as minimum business hours, excluding the current provider's own holidays. And the request itself has a deadline inside the day: it must reach the losing provider by 1 p.m. local time to activate at midnight.

> An accurate and complete Local Service Request (LSR) must be received by the current service provider between 8 a.m. and 1 p.m. local time for a simple port request to be eligible for activation at midnight on the same day.

An LSR arriving after that window counts as received at 8 a.m. the next business day.

A request that is not simple has its own interval in the same rule: four business days. A carrier holding a Commission waiver of the one-day interval also has four. And the rule counts a port involving interconnected VoIP service as intermodal, so a VoIP number is inside the rule rather than outside it.

Which of the two intervals applies turns on whether the request is simple. Part 52 sets both intervals without defining that term. The receiving provider classifies the request, so ask which category yours falls into before you fix a cutover date.

Outside the US, each regulator sets its own process, so a single worldwide interval does not exist.

## What does the receiving provider need?

Records that match the losing provider's, and authorization from whoever holds the account.

The sequence is the same wherever the market rules differ. You confirm the number is eligible with the receiving provider, authorize the transfer as the account holder, and supply details that match what the losing provider has on file.

In the US the rule caps what may be asked. [47 CFR 52.36](https://www.ecfr.gov/current/title-47/chapter-I/subchapter-B/part-52/subpart-C/section-52.36) lets a carrier require only the fields it lists for a simple port, among them the ported number, the account number and the zip code. Account name and service address are not on that list. A mismatch in the fields that are on it is what gets a request rejected, because the losing provider matches your request against its own record.

A transfer date is then agreed rather than assumed. Keep the original service active until the number is confirmed working on the new provider, because cancelling first releases the number and ends the transfer.

## Is the port the end of the work?

No. The carrier transfer and the services on top of it are separate.

A completed port means calls and texts to that number arrive at the new provider. It does not mean they arrive anywhere useful yet. Inbound routing has to be configured. Messaging needs its own sender registration, which is a separate approval on its own timeline. [Sender ID registration](/explained/sms/what-is-sender-id-registration) covers what that involves.

So a port is finished when the number does what the old one did, not when the carrier confirms the move.

## What can I do on Bird?

Ask about eligibility first, because a port is not a self-service operation.

There is no port-in operation in the public API. `POST /v1/numbers/orders` purchases an available number from inventory, which is a different thing from transferring one you already hold. On the read side, requesting the `porting` property in a lookup returns whether the number has moved network, when it last did, and its porting record. That describes history rather than requesting a transfer.

So start with [contact sales](/contact-sales), naming the market, the number type and the services the number has to carry. Treat the answer as an eligibility question rather than an acceptance. Once a number is on the account, [buying and releasing numbers](/docs/guides/numbers/buying-numbers), [receiving calls](/docs/guides/voice/receiving-calls) and [SMS senders](/docs/guides/sms/senders) cover its services.

## Related resources

- [SMS numbers](/products/sms/numbers) (product)
- [Number types](/docs/guides/numbers/number-types) (docs)
- [What is a virtual phone number (VMN)?](/explained/numbers/what-is-a-virtual-phone-number) (answer)

[Get an implementation brief](/learn/workspace?topic=phone-numbers)