How to Switch Networks and Keep Your Number (PAC Code Guide)

Switching your mobile network used to be a hassle. Today, thanks to Ofcom regulations introduced in 2019, the entire process can be done in minutes via text message — and your number transfers within one working day. Here's a step-by-step guide.

What Is a PAC Code?

A PAC (Porting Authorisation Code) is a unique code your current mobile provider must give you when you want to take your phone number to a new network. The code is nine characters long (letters and numbers) and is valid for 30 days.

Under Ofcom rules, your current provider must give you your PAC code immediately — either via text within seconds of requesting it, or over the phone. They cannot delay, charge you for it, or pressure you to stay (though they can make a retention offer, which you're free to refuse).

Step-by-Step: How to Switch

Step 1: Find a Better Deal

Before you switch, compare your current plan with available alternatives. Use our compare tool or deals page to see the latest SIM-only offers.

Step 2: Request Your PAC Code

The easiest method — text: Send the text PAC to 65075 from the phone you want to keep. You'll receive a text back within seconds with your PAC code and instructions.

By phone: Call your current provider's customer services. They must give you the code during the call. Note: they may attempt to retain you with a better deal — only accept if it genuinely beats the new offer you've found.

Step 3: Order Your New SIM

Sign up with your new network and choose your new plan. During the sign-up process, you'll be asked if you want to keep your existing number. Select yes and enter your PAC code when prompted.

Most networks let you order either a physical SIM or an eSIM (if your phone supports it).

Step 4: The Porting Process

Once your new network receives your PAC code, they'll arrange the number transfer. This typically happens:

• Same day if you submit before midday on a working day
• Next working day if you submit after midday, or on weekends/bank holidays

During the brief switchover window (usually a minute or less), you may experience a short loss of service. Most people don't notice this.

Step 5: Activate Your New SIM

When your number has ported, your old SIM will stop working. Insert your new SIM (or activate your new eSIM) and follow any setup instructions from your new network.

Make sure your phone is unlocked. If you bought your phone on contract from a network, it may be locked to that network. Contact your old provider to request an unlock — most networks unlock phones for free.

Important Things to Know

Check for Early Termination Fees

If you're still within a contract period, leaving early typically incurs a fee. This is usually the cost of the remaining months' bills. Calculate whether the savings on the new plan outweigh the exit fee before switching.

What Happens to Your Old Contract?

Requesting a PAC code does not automatically cancel your old contract. You may need to separately notify your provider that you're leaving and request cancellation. Check your contract terms — some providers will auto-cancel when the PAC code is used; others require a separate notice.

SIM-Only vs Phone Contracts

If you're coming to the end of a phone contract, you can keep using the same phone and move to a much cheaper SIM-only deal. Many people save £15–£30 per month by doing this at the end of their 24-month contract.

The STAC Code (for Non-Porting Switches)

If you want to leave your current network but don't want to keep your number, you can request a STAC (Service Termination Authorisation Code) instead. The same Ofcom rules apply — it must be given immediately via text to 75075.

Frequently Asked Questions

Will I lose my number during the switch? No. Your number stays the same throughout the porting process. There's only a very brief window (seconds to a minute) during the actual transfer when service may be unavailable.

Can I use my PAC code if I'm still in contract? Yes — but you may owe an early termination fee. Your provider must still give you the code and cannot refuse.

What if my PAC code expires? PAC codes are valid for 30 days. If yours expires, simply request a new one.

Can I switch and get a new number? Yes. Just don't use a PAC code during sign-up — you'll automatically be assigned a new number by your new network.

Summary

Switching mobile networks is quick, straightforward, and free. Text PAC to 65075, wait for your code, sign up with your new network using the code, and your number moves within one working day. The process takes about 5–10 minutes of your time, and the savings can be significant.

Use our deals comparison to find the best SIM-only plan before you make the switch.