Requirements · Mobile plans
How to switch mobile provider and keep your number
Last updated 25 October 2026 · 2 sources listed · Reading time about 4 minutes
Short answer
Keeping your number usually relies on a number portability process where the new provider coordinates the transfer, using an authorisation code or account details from the old one. Settle any device balance and contract end date first, confirm the handset is unlocked and compatible, and expect a short gap while the line moves over.
Who this is for: A mobile customer who wants to move to another network without losing their phone number, and needs to know what to prepare and what could go wrong.
What to evaluate
Contract end date and exit liability
Leaving before the term ends can trigger early termination charges and a demand for the remaining device balance.
How to check: Ask your current provider for the end date and a written settlement figure, and compare it with the benefit of moving.
Handset lock status and compatibility
A locked or incompatible device will not work on the destination network, and some older handsets lack bands or features the new provider relies on.
How to check: Request unlocking if needed, and ask the new provider to confirm in writing that your model supports voice, messaging and data on their network.
Portability authorisation method
Different regions use a code, a PIN or account identifiers. Errors in these cause rejected transfers and delay.
How to check: Learn which method your country uses, request the code from your current provider, and note any expiry on it.
Timing of the transfer
Porting has a window in which service can be interrupted briefly, and it can clash with travel or an important call.
How to check: Ask the new provider for the expected transfer time and schedule it when brief disruption would not matter.
Notice period and overlap
If you cancel separately instead of porting, you may lose the number or pay for overlapping service.
How to check: Check whether porting automatically terminates the old agreement and whether any notice is still required.
Account-linked services
Banking one-time codes, two-factor authentication and messaging apps often depend on the number, so a gap or a changed SIM can lock you out.
How to check: List services that text you codes and prepare alternative verification methods before the switch.
eSIM or physical SIM delivery
A physical SIM takes time to arrive, while an eSIM requires a compatible device and an activation method that works only with a data connection.
How to check: Confirm which type is offered, how activation works, and what you will use for connectivity while it is being set up.
Comparison
| Route | What you need | Risk |
|---|---|---|
| Port-in coordinated by the new provider | Authorisation code or account identifiers from the old provider | A mismatched name or code can cause the request to be rejected. |
| Cancel old plan, then start fresh | Nothing from the old provider except cancellation | You lose the number and must update every account that relies on it. |
| Temporary second SIM during transition | A dual-SIM phone or spare handset | Paying for two services briefly and managing which line receives codes. |
| Move within the same provider to a different plan | A request through the provider's account channels | Unintended contract restart or loss of loyalty terms. |
| Convert physical SIM to eSIM on the same network | A compatible device and account verification | SIM swap scams exploit weak identity checks, so protect the account with extra security. |
Decision worksheet
Rate up to three options against this guide’s own criteria. It runs in your browser and saves only on this device. It is a thinking aid, not a recommendation.
1. Have you checked each criterion?
0 of 7 criteria checked.
2. Compare options (0 = fails or unknown, 3 = meets it well)
| Criterion | |||
|---|---|---|---|
| Contract end date and exit liability | |||
| Handset lock status and compatibility | |||
| Portability authorisation method | |||
| Timing of the transfer | |||
| Notice period and overlap | |||
| Account-linked services | |||
| eSIM or physical SIM delivery | |||
| Total (max 21) | 0 | 0 | 0 |
Questions to ask before you commit
- What is my exact contract end date and what is the written settlement figure if I leave early?
- How do I obtain the transfer authorisation, and how long is it valid?
- Will my old plan end automatically when the port completes, or must I cancel separately?
- Is my handset unlocked and will it support all the features on the destination network?
- How long will the transfer take and will I lose service during that time?
- Will I be charged for the old plan after the transfer date, and until when?
- What happens to any voicemail, visual voicemail or linked services during the move?
- Is a physical SIM or an eSIM offered and how is it activated?
Typical trade-offs
Switch now with an exit charge or wait for the term to end
- Upside
- Moving immediately gets you a better plan or coverage sooner.
- Downside
- Settlement can outweigh the savings, and waiting often costs nothing beyond patience.
Port the number or start with a fresh one
- Upside
- Porting avoids notifying contacts and re-registering services.
- Downside
- A transfer can fail or delay, and fresh numbers avoid that but force many account changes.
eSIM or physical SIM
- Upside
- An eSIM can be activated without waiting for delivery and cannot be physically lost.
- Downside
- Moving between devices can be fiddly and some older phones cannot use one.
Common mistakes
- Cancelling the old line before porting. That can release the number permanently, so start the port with the new provider first.
- Entering account details that differ from the old provider's records. Names, addresses and identifiers must match exactly.
- Forgetting two-factor codes. Move authentication to an app or alternate method before switching.
- Assuming the handset is unlocked because it is paid off. Confirm status explicitly with the seller.
- Leaving a balance unpaid on the old account, which can lead to collection activity even though the number has moved.
Related questions
How does number portability work?
In most regions you ask the destination provider to take over your number, and they request release from the current provider through an industry process. You normally prove ownership with a code, PIN or account details. Once validated, the number is switched at an agreed time and your new SIM begins carrying calls and texts. The old provider cannot usually refuse a valid request, though they may remind you of any outstanding contract liabilities.
Will I lose service during the transfer?
Usually there is a short interruption while the number points to the new network, and it can be longer if details are wrong or the request is queued. Providers often schedule the cutover for a window you can plan around. Keep your old SIM active until the new one works, and have a second way to receive important codes so that a gap in messaging does not lock you out of accounts.
Can I port my number if I still owe on my phone?
Portability and debt are separate in most systems, so you can often move the number while still owing money. What changes is that early termination or device balances become due according to your contract, and the old provider may bill them separately. Request a settlement figure before you decide, and check whether the new provider offers help covering exit costs. Do not assume a balance disappears when the number moves.
What is a SIM swap scam and how do I protect against it?
A SIM swap scam occurs when someone persuades a provider to move your number to a SIM they control, allowing them to receive your verification codes. Protect yourself by adding a verbal passcode or account PIN, being cautious with personal information online, and favouring authenticator apps over text-message codes for sensitive accounts. If your phone suddenly loses signal without explanation, contact the provider promptly from another device.
Do I have to tell my current provider that I am leaving?
When porting, the process itself informs them, and the old service normally ends when the transfer completes. However, practice differs, and some agreements still require written notice or incur charges after the port date. Ask the new provider what happens to the old plan, and confirm with the old provider that the account will close without extra charges. Keep copies of the confirmation in case a final bill arrives unexpectedly.
Sources and further reading
These pages were reachable when we last checked. They informed definitions and rules referred to above; they do not endorse this guide. Where rules differ by country, check the authority for your location.
- Consumer help center — Federal Communications Commission, retrieved 27 October 2026
- National Cyber Security Centre — NCSC, retrieved 27 October 2026
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