Mobile phones in the UK: SIM cards, contracts and cheap calls to Poland

In short

• There are three main types of deal: pay as you go (top-ups, no contract and no credit check), SIM-only (just the SIM, on a monthly or longer contract) and a contract with a handset (pay monthly with a device). With a contract, the provider usually checks your credit history.
• Before choosing a network, check the coverage at your address on Ofcom's free Map Your Mobile checker.
• You can switch and keep your number with a free text: PAC to 65075 (keep your number) or STAC to 75075 (don't keep it). The code is valid for 30 days, and your new provider completes the switch within 1 working day.
• In contracts taken out from 17 January 2025, mid-contract price rises must be set out in pounds and pence, not as a percentage or linked to inflation.
• Since 17 December 2021, mobile providers in the UK must sell handsets unlocked.
• To call Poland, dial +48 or 0048 followed by the 9-digit number. Inclusive minutes usually cover UK numbers only, so check the international rates or call over the internet.
• Free roaming in the EU is not guaranteed after Brexit, and a Polish SIM used in the UK is not covered by the ‘Roam Like at Home’ rule.
• Forward suspicious texts free of charge to 7726. The emergency numbers 999 and 112 are always free.

Pay as you go, SIM-only or a contract with a handset

Ofcom describes three types of deal:

Pay as you go (PAYG) is a top-up SIM. According to Ofcom, there is no long contract and no credit check, which makes it a good option for your first few weeks in the UK. Credit usually doesn't expire on a set date, but you need to use the SIM or top up from time to time to keep the number active. Many PAYG deals also offer bundles of minutes, texts and data for 30 days. According to Citizens Advice, PAYG can help you budget, but it may work out more expensive if you use your phone a lot.

SIM-only is just a SIM card with a monthly plan. Ofcom says it is usually the best value if you already have a phone or are happy to buy a new or refurbished one separately. The contract can be monthly (rolling) or for 12 or 24 months. A shorter contract gives you the freedom to change network.

A contract with a handset (pay monthly with a device) spreads the price of the phone over instalments. Ofcom advises working out the total cost over the whole contract, including any extras, not just the monthly price. Compare it with the cost of SIM-only plus a phone bought separately.

An eSIM is a SIM built into the phone, which the provider activates remotely, with no plastic card. Not every phone supports it, so check before you buy an eSIM deal.

Credit checks for contracts

With a monthly contract, the provider usually checks your credit history (credit check). If you've only just moved to the UK, you may not have a UK credit history yet, so a contract can be harder to get. In that case, start with PAYG, which needs no credit check, and build your credit history in the meantime. Our guide Credit score in the UK: how to check and improve it explains how.

Networks, MVNOs and coverage

The UK has a few networks with their own infrastructure (mobile network operators, MNOs). Many other brands are mobile virtual network operators (MVNOs): according to Ofcom, they don't own the network infrastructure and use one of the big operators' networks to sell their own deals. An MVNO's coverage therefore depends on the network it uses. Before you sign up, ask which network that is and check its coverage.

How to check coverage: enter your postcode in Ofcom's free Map Your Mobile checker. For each network, it shows predicted 4G and 5G coverage indoors and outdoors, plus a performance score for your area based on measurements from users' phones. The results are a guide and may differ from the maps on providers' websites, because Ofcom compares all networks against a single standard. Check both your home and work addresses.

Weak signal at home: according to Ofcom, many networks let you make calls over Wi‑Fi (Wi‑Fi calling). Some networks switch it on automatically, others need an app, and not every phone supports it, so ask your provider.

Keeping your number and switching network

According to Citizens Advice and Ofcom, switching mobile provider works like this:

1. To keep your number: text PAC to 65075. If you don't want to keep your number: text STAC to 75075. Both texts are free.
2. Your current provider replies by text with a code valid for 30 days and details of any charges for ending your contract early, plus your remaining credit if you're on PAYG.
3. You give the code to your new provider, who completes the switch within 1 working day. You don't need to call your old provider again.
4. If the switch takes longer than 1 working day or your provider abuses the process, Ofcom says you are entitled to compensation from your provider.

Also:

• A free text saying INFO to 85075 tells you whether you'll pay a fee to leave your contract (exit fee).
• Ofcom has banned charges for notice periods that run after the switch date, so you don't pay twice for the same period.
• If you have several numbers on one account (for example a family plan), you'll need to switch online or by phone rather than by text.
• You can usually cancel a contract taken out by phone or online free of charge within 14 days (cooling-off period). According to Citizens Advice, you don't have this legal right if you signed up in a shop.

Price rises during your contract

According to Ofcom, from 17 January 2025 phone, broadband and pay-TV providers can't include inflation-linked or percentage-based price rises in new contracts. If a contract includes an annual price rise, it must be set out in pounds and pence at the point of sale. Ofcom hasn't banned price rises altogether; it only sets out how they must be written into the contract.

• Contracts taken out before 17 January 2025 can still include percentage or inflation-linked rises.
• According to Citizens Advice, if your contract terms don't allow annual price rises, your provider must give you 30 days' notice of a price rise, and during that time you have the right to leave without a fee.
• Before signing, check how much and when the price will go up, and add that to the total cost.

The end of your contract and unlocked phones

End-of-contract notifications: according to Ofcom, your provider must contact you (by text, email or letter) between 10 and 40 days before your minimum contract period ends. The notification includes the end date, the notice period, your current and future price and the provider's best deals, including those for new customers. If you have a contract with a handset, at least one of them must be a SIM-only deal. If you stay with the provider after the contract ends, you'll get information about its best tariff once a year.

This is a good moment to decide. On a contract with a handset, check whether your monthly charge goes down once the phone is paid off. If it doesn't, compare it with SIM-only deals from the same provider and from other networks.

Unlocked phones: since 17 December 2021, providers in the UK have been banned from selling handsets locked to one network (Ofcom). A phone bought from a provider after that date works with any network's SIM. A phone bought earlier or abroad may be locked. In that case, ask the provider you bought it from how to unlock it.

How to call Poland cheaply

How to dial: a Polish phone number has 9 digits (UKE, the Polish telecoms regulator). From a UK phone, dial +48 or 0048 (00 is the international access code in the UK under Ofcom's numbering plan), followed by the 9 digits, for example +48 501 XXX XXX. Save contacts in your phone with +48 from the start: they'll work both in the UK and in Poland.

What your allowance covers: inclusive minutes on UK deals usually cover calls to UK numbers (mobiles starting 07 and landlines starting 01, 02 and 03). Calls to Poland are usually charged separately, often per minute, and can be expensive. Before your first call, check your provider's price list for:

• the rate per minute and per text to Poland (separately for mobiles and landlines),
• whether your deal includes international minutes or whether you can buy an international add-on (bundle) with minutes to selected countries,
• whether international calls are enabled on your SIM at all.

Calling cards and access numbers: according to Citizens Advice, you're charged for calling a number that connects you to another number (an indirect access number). Some international calling cards use these numbers, so add their cost to your provider's charge. Also watch out for 09 numbers (premium rate) and 0843, 0844 and 0870–0873 numbers, which Citizens Advice says usually cost more than ordinary calls.

Calls over the internet: messaging apps and internet calling apps let you call Poland without per-minute charges. They use mobile data or Wi‑Fi rather than the minutes in your allowance. This is usually the cheapest option if the person in Poland also has a smartphone and internet access.

Roaming: trips to Poland and the EU

A UK SIM abroad. After Brexit, free roaming in the EU is not guaranteed: each provider decides whether and how much to charge for using your phone abroad. Check the terms before you travel. According to Ofcom:

• Since 1 October 2024, your provider must notify you when you start roaming: about charges, any fair use or time limits and the option to set a spending limit. The rules also cover inadvertent roaming, for example near a border, when your phone connects to a network in the neighbouring country.
• The earlier rules with a legal limit of £45 a month on data roaming charges stopped applying on 1 July 2022. Some providers still apply such a limit voluntarily (as of October 2026). Ask your provider what limit it applies.
• You can set a bill limit. Since 1 October 2018, providers have had to offer this option to new customers and to customers extending their contract. Your provider will warn you when you're close to the limit and can't go over it without your express consent. If roaming is included in your contract, the limit also applies abroad.

A Polish SIM in the UK. Since 1 January 2021, the ‘Roam Like at Home’ (RLAH) rule no longer covers the United Kingdom (UKE). A Polish provider can therefore charge different prices for calls, texts and data in the UK than in the EU, and the extra charges can be high. UKE advises checking your provider's terms, turning off mobile data, using Wi‑Fi or buying a UK pay as you go SIM. If your phone takes two SIMs (for example a SIM card and an eSIM), you can keep a Polish number alongside a UK one, for example for texts from your bank, but check with the provider how much it costs to keep the number and receive calls in the UK.

Text scams and emergency numbers

• Forward a suspicious text free of charge to 7726 (NCSC). Your provider can look into the sender and block them. Don't tap links in unexpected messages about parcels, fines or tax refunds. To learn more about spotting scams, read our guide Scams in the UK: how to spot them and where to report them.
• If you've lost money, report it: in England, Wales and Northern Ireland at reportfraud.police.uk or on 0300 123 2040, and in Scotland to the police on 101.
• The emergency numbers 999 and 112 work across the UK and, according to Citizens Advice, are always free from mobiles and landlines. 101 (police, non-emergencies), 105 (power cuts) and 111 (NHS) are also free.

If you can't pay your bill

According to Citizens Advice, contact your provider as soon as possible if you think you'll miss a payment. Your provider may, for example, give you more time to pay, spread the debt over instalments or move you to a cheaper deal. If you're struggling financially, it may also let you leave your contract without a fee.

People on certain benefits (such as Universal Credit) may be able to get a cheaper social tariff for broadband or phone. If your provider has one, moving to it is free. Ofcom keeps a list of providers offering these deals.

If you keep not paying, your provider may restrict your service (for example to emergency calls only), disconnect you, pass the debt to a debt collection agency or take you to court.

Where to get help and how to complain

Complaints: first complain to your provider. Every provider must belong to one of two Ofcom-approved alternative dispute resolution (ADR) schemes. Since 8 April 2026, you can go to the scheme if the problem hasn't been resolved within 6 weeks of your complaint (previously 8 weeks) or if you receive a final response (deadlock letter). You can find out which scheme your provider belongs to in its complaints code. Both schemes are free:

• Communications Ombudsman – free dispute resolution with phone and broadband providers.
• CISAS – the Communications and Internet Services Adjudication Scheme, free for customers.

Advice:

• Citizens Advice – consumer helpline 0808 223 1133 (England, free). In Scotland, consumer advice is provided by Advice Direct Scotland.
• Ofcom – advice for phone customers, the coverage map and the list of social tariffs.

This guide is general information and is not a substitute for legal or financial advice. Prices and deal terms change often, so check the latest information with the provider and in the sources before signing a contract.