How to Switch Business Mobile Provider (PAC & STAC, 2026)

Most businesses stay on the wrong mobile deal for one reason: they think switching will be painful. They picture downtime, lost numbers, staff cut off mid-day, and a week of admin nobody has time for. In reality, switching business mobile provider in the UK is a regulated process designed to be quick and clean - your numbers are protected, the gaining provider does most of the work, and a well-run fleet port causes no service gap at all. As the person who has moved our own estate and helped clients move theirs, I can tell you the fear is almost always bigger than the job. This guide explains exactly how to switch in 2026 - PAC and STAC codes, porting a whole fleet, timing the move around your contract, and avoiding the few genuine pitfalls. When you are ready to compare what the market would offer your team, get a business mobile quote and we will manage the switch for you.

PAC vs STAC: which code do you need?

UK switching runs on two short codes, and the only question is whether you want to keep your numbers:

• PAC (Porting Authorisation Code) - use this when you want to keep your numbers. The PAC tells the gaining provider which number to port across. This is what almost every business wants, because your numbers are on your website, your email signatures, your customers' phones and your Google listing.
• STAC (Service Termination Authorisation Code) - use this when you want to leave without keeping your numbers - for example, a line you are retiring entirely. Using a STAC cancels the old service cleanly so you are not double-billed.

Getting either code is simple and free. Text PAC to 65075, or STAC to 75075, from each line - or, for a business account, request them in bulk through your account team. You will usually receive the code within a minute (by law, within one working day), and it stays valid for 30 days. You then hand it to the gaining provider, who does the rest.

How the switch actually works, step by step

The mechanics are the same whether you are moving one line or two hundred:

1. Choose your new provider and plan. Compare the market on coverage at your postcodes, pricing and terms - our network comparison covers the EE/Vodafone/O2 decision, or we can run the comparison for you.
2. Check your exit position. Confirm your minimum term end date and any early termination fee before you start. More on this below.
3. Request your PAC or STAC codes - per line by text, or in bulk via your account team for a fleet.
4. Give the codes to the gaining provider. They schedule the port and order the new SIMs or eSIMs.
5. The port completes, typically by the end of the next working day per batch. Your number moves to the new network; the old contract terminates.
6. Enrol and distribute the new SIMs. Ideally the new SIMs land already enrolled in your MDM so security is sorted from day one.

There is no need to tell customers anything - your numbers are unchanged. The switch is invisible from the outside.

Will we lose service during the switch?

This is the question that keeps businesses on the wrong deal, and the honest answer is: not if it is done properly. A port is scheduled for a specific window, and the cutover from old network to new is near-instantaneous for each number. The old SIM stops working as the new one activates. The practical risks are small and manageable:

• Activate the new SIM before the port window so the handset is ready when the number lands.
• Port in waves for a fleet (see below) so any individual issue is contained.
• Keep eSIM-capable handsets in mind - eSIMs make the swap faster still, with no physical SIM to post or fit, and let you trial the new network before committing. Our guide to eSIMs for business covers this.

Done with a little planning, the typical experience is that staff notice nothing beyond a brief moment where the new SIM takes over.

Porting a whole fleet without the drama

Moving forty or two hundred lines sounds daunting; it is just one-line porting, organised. The principles:

• Stagger the port in waves. Move a pilot group first, confirm it went cleanly, then move the rest in batches. A snag then affects a handful of users, not the whole company on the same morning.
• Use a provider that project-manages it. A good business provider handles bulk PAC requests, schedules the waves, coordinates SIM delivery and is on hand during cutover. This is exactly the kind of legwork a reseller earns its place doing.
• Sort security on day one. New SIMs and handsets should arrive already enrolled in your MDM, not "we'll set that up later" - the gap between distribution and enrolment is exactly when a lost device becomes a data incident. See what to do if a phone is lost or stolen.
• Brief staff briefly. A two-line message - "your new SIM arrives Tuesday, pop it in when prompted, your number stays the same" - prevents most support calls.

Timing: when to switch

The mechanics are easy; the money is in the timing. Switch at the wrong moment and you pay an exit fee you could have avoided; switch at the right moment and you move cleanly with maximum leverage.

• Around 90 days before your contract ends is the sweet spot. You have time to compare the market, negotiate with your incumbent from strength, and complete the port to land just as the old term expires - no exit fee, no gap.
• Check your notice period. Some contracts require notice before the end date, or auto-renew if you do nothing. Find that window in your contract today - our contracts guide explains the mechanics.
• Out of contract? Switch whenever. Lines past their minimum term can move with no exit fee, and they are almost certainly drifting at full rates with no discount, so the sooner the better.

What about early termination fees?

Requesting a PAC or STAC is free and cannot be blocked - but leaving before your minimum term ends still triggers any early termination fee (ETF) you owe. The standard model is the remaining monthly charges to the end of term (often partially discounted), plus any unpaid handset balance on bundled deals, since the phone was financed as a loan.

That does not always mean waiting. Sometimes paying the ETF is the right financial call - if a legacy contract carries inflation-linked rises and oversized allowances, the exit fee can pay for itself in savings within months. Run the numbers: total the ETF, compare it against the saving from a better deal over the remaining months, and decide on the maths rather than the instinct that you are "stuck." Our guides to what business mobile costs and contract lengths give you the benchmarks.

Common switching mistakes to avoid

• Letting the contract auto-renew first. Miss the notice window and you can be re-committed for another full term before you have even compared the market. Diarise renewal dates.
• Requesting PACs before you have a plan in place. The code is valid 30 days; get your new provider and SIMs lined up so you use it within the window.
• Porting the whole fleet in one go. Stagger it. Always.
• Forgetting non-handset connections. Data SIMs, routers and IoT lines need porting or cancelling too - don't leave a stray contract running.
• Ignoring coverage. Switching to a cheaper network with weak signal at your sites is a false economy. Check coverage at your postcodes before you move.

The bottom line

Switching business mobile provider in 2026 is a regulated, well-worn process: request a PAC to keep your numbers (or STAC to leave), hand it to the gaining provider, and the port completes within about a working day per batch with no need to tell a single customer. The fear of downtime keeps far more businesses overpaying than any real difficulty does. Time the move for around 90 days before your contract ends, stagger a fleet in waves, sort security on day one, and the whole thing is painless. If you want the comparison run and the switch managed for you, get a business mobile quote and we will handle the PACs, the porting and the rollout across EE, Vodafone and O2.