Quick picks
Your phone does a lot of work on a UK trip: it is your Tube ticket (through Apple Pay or Google Pay), your train ticket, your map, your taxi and often your restaurant booking. Getting data sorted before you land saves stress at the airport and money on your bill.
- Short trip, don't want to fuss: use your US carrier's plan. On T-Mobile's Experience plans you already have some data; on AT&T or Verizon, a day pass costs about $12 a day.
- A week or more, phone unlocked: buy a travel eSIM before you leave or a UK SIM or eSIM on arrival. It usually costs a fraction of a day pass.
- Long stay, study or work: get a UK monthly SIM-only plan with a UK number. See Long stays.
- Everyone: bring a Type G plug adapter, check your chargers say 100–240 V, and download the apps below before you fly.
What US carriers include in the UK
All the big American carriers work in the UK by roaming on British networks, so your phone will usually connect the moment you switch it on after landing. What you pay depends on your plan, and roaming charges have caught out plenty of travelers. Check your plan in your carrier's app before you go. These are the main options as of October 2026.
AT&T
AT&T's International Day Pass costs $12 a day for the first line and $6 a day for each additional line used that same day. It works on eligible unlimited plans and gives you your plan's talk, text and data abroad, with calls back to the US included. You're charged only for days you actually use your phone on a cellular network. On a 10-day trip that's $120 for one person, or $180 for a couple.
Verizon
Verizon's TravelPass also costs $12 a day in the UK and more than 210 other destinations. Verizon says TravelPass is added automatically on its Unlimited Plus and Unlimited Welcome plans, which generally means the daily fee starts on any day you use your phone on a network abroad. Its International Monthly Plan, at $100, includes 20 GB of high-speed data, unlimited texting and 250 minutes, and Verizon pitches it for trips of nine days or more. The top Unlimited Ultimate plan already includes international data, talk and text, so you don't add TravelPass; check its high-speed data allowance.
T-Mobile
T-Mobile is the most generous of the big three for casual travelers. Its Experience More plan includes up to 5 GB of high-speed data in more than 215 countries, including the UK, and Experience Beyond includes up to 15 GB; after that you get unlimited data at a slow 256 kbps. Texting is unlimited. Calls cost $0.50 a minute, though calls to the US over Wi-Fi are free. Older plans such as Magenta and Go5G also include basic data and texting abroad. If you need more fast data, T-Mobile sells International Passes; check current prices in the T-Life app.
Other US carriers
- Google Fi includes data abroad on its higher-tier unlimited plans and is popular with frequent travelers.
- Budget and prepaid carriers (Mint, Visible, US Mobile, Cricket, Metro and others) vary widely. Some include a few roaming days or sell add-ons; many include nothing, and some block roaming altogether. Check before you go.
- Cable carriers (Xfinity Mobile, Spectrum Mobile) sell their own international options, usually priced per day or per gigabyte.
Watch out
A day pass can be triggered by a single background app refresh or one outgoing text. If you don't want to pay, turn off cellular data roaming on your US line before the plane lands, or keep the phone in airplane mode with Wi-Fi on. Check your carrier's terms for what starts the clock.
Insider tip
Turn on Wi-Fi Calling before you leave. With it on, calls and texts to US numbers over hotel or café Wi-Fi are usually free on AT&T, Verizon and T-Mobile, and you keep your US number for two-factor codes from your bank.
Travel eSIMs
An eSIM is a digital SIM card you download onto your phone by scanning a QR code or tapping a link in an app. A travel eSIM gives you a UK data plan while your US line stays on the phone for calls and texts. For most travelers on trips of a week or longer, it is the cheapest, easiest option.
How it works
- Check that your phone supports eSIM (iPhone XS and later, Google Pixel 3 and later, and most recent Samsung Galaxy phones) and that it is carrier-unlocked. Phones still on a payment plan are often locked; ask your carrier to unlock it a few weeks before you travel.
- Buy a UK or Europe plan from a seller such as Airalo, Holafly, Nomad, Saily or Ubigi. Prices change often, but a 10 GB, 30-day UK plan commonly costs roughly $10–25. Unlimited plans cost more.
- Install the eSIM at home on Wi-Fi, but don't switch it on yet. Label it "UK data" in your phone's settings.
- When you land, set the travel eSIM as your line for mobile data and turn on data roaming for that line only (travel eSIMs technically roam).
- Keep your US line switched on for calls and texts, with its data roaming turned off, so you still receive bank codes without triggering a day pass. Check your carrier's terms: receiving texts is usually free, sending them may not be.
Most travel eSIMs are data only, with no UK phone number. That's fine for most people: WhatsApp, FaceTime, iMessage and Wi-Fi Calling cover calls and messages. If you need a UK number (for restaurant bookings, a UK bank, or a semester abroad), get a UK SIM instead.
Different from home
US-model iPhones from the iPhone 14 onward have no physical SIM slot, so a UK plastic SIM won't fit. Choose a UK network's eSIM or a travel eSIM instead. Many Android phones still take both.
Europe on the same trip
If you're adding Paris, Ireland or the rest of Europe, buy a regional Europe plan that names the UK, since a few Europe eSIMs leave the UK out after Brexit. See Ireland and Europe.
UK SIM cards and UK eSIMs
A British SIM or eSIM gives you a UK number starting with 07 and local rates. It makes sense for trips of two weeks or more, for heavy data users, and for anyone who will be texting B&B hosts, booking tables or getting delivery updates. Your phone must be unlocked.
The networks
The UK has four big network brands. In 2025 Vodafone and Three merged into one company, VodafoneThree, though both brands still operate separately for customers.
- EE (owned by BT): generally the widest coverage, including in many rural areas. A good choice for the Highlands and countryside.
- Vodafone: strong in cities and along main roads and rail lines.
- O2 (Virgin Media O2): good urban coverage, and its customers get free Wi-Fi in Tube stations.
- Three: often the best value for big data bundles, strongest in cities and towns.
Budget brands ride on those networks: giffgaff and Tesco Mobile use O2; Voxi and Lebara use Vodafone; Smarty uses Three; Lycamobile uses EE. They are usually cheaper than the big names for the same data.
What to buy
Look for a 30-day prepaid bundle, which the UK calls "pay as you go" or "SIM only" with no contract. Bundles commonly start around £10 (about $13) for a month with a decent data allowance, and £20–30 (about $27–40) gets you large or unlimited data. Check allowances on the network's own site, since they change often.
- Where to buy: network shops on most high streets, supermarkets (Tesco, Sainsbury's), WHSmith and Boots, and vending machines and shops at airports. Airport SIM shops often sell pricier "tourist" packs; a high-street shop or a network's own website is usually cheaper.
- eSIM: EE, Vodafone, O2, Three and giffgaff all offer eSIMs, usually set up in their apps. Some ask for a UK address or a UK card for online orders; buying in a shop avoids that.
- ID: you don't need ID to buy a prepaid SIM in the UK.
- Roaming into Europe: UK networks no longer include free EU roaming as standard. Some bundles include it; others charge a daily fee. Check before you take a UK SIM to Paris or Dublin.
Watch out
The UK's networks have switched off nearly all of their 3G, with O2 the last to finish. Phones that can't make calls over 4G (called VoLTE or "4G Calling") may lose voice calls on some UK SIMs. Any iPhone or Android phone from the last several years is fine; an old backup phone may not be.
Calling, texting and numbers
UK mobile numbers start with 07 and have 11 digits (07xxx xxxxxx). From a US phone, dial +44 and drop the leading 0: +44 7xxx xxxxxx. London landlines start 020; other areas have their own codes (0131 Edinburgh, 0161 Manchester, 029 Cardiff, 028 Northern Ireland).
To call the US from a UK phone, dial +1 and the number. Calls from a UK SIM to the US cost extra on most pay-as-you-go bundles, so most travelers use WhatsApp or FaceTime over data or Wi-Fi. WhatsApp is the default messaging app for many Brits, from B&B hosts to tour guides, so install it before you go.
Numbers starting 0800 and 0808 are free from UK phones. Numbers starting 084, 087 and 09 cost extra, sometimes a lot, especially from a roaming US phone.
Wi-Fi
Free Wi-Fi is easy to find in Britain. Hotels, B&Bs and holiday cottages almost always include it, though speeds at remote country properties can be slow or satellite-based. Most cafés (Pret, Costa, Caffè Nero, Starbucks and independents), many pubs including Wetherspoon, museums, libraries, shopping centers and big rail stations offer free Wi-Fi, often after you sign in with an email address.
Trains, buses and ferries
Most long-distance train operators, including LNER, Avanti West Coast, GWR, CrossCountry, ScotRail and Transport for Wales, offer free onboard Wi-Fi, as does Eurostar. It works for email and messaging and gets patchy in rural cuttings and tunnels, so download films before you board. Many National Express coaches and some regional buses have Wi-Fi; ferries vary.
Tube station Wi-Fi
Virgin Media provides Wi-Fi at more than 97% of London Underground stations, in ticket halls and on platforms. It's free for customers of Virgin Media, EE, O2 and Three, who connect automatically or through their network's app. Visitors on US plans or travel eSIMs generally can't use it, which matters less now that mobile signal is spreading through the tunnels.
Insider tip
On public Wi-Fi, avoid logging in to your bank unless you're using its app, and consider a VPN. Watch for fake hotspots with names close to a café's real one, and ask staff for the exact network name.
Mobile signal on the Tube
For decades the deep Tube tunnels had no phone signal at all. That's changing fast. A company called Boldyn Networks has been fitting 4G and 5G coverage across the Underground for TfL, and all four UK networks (EE, O2, Vodafone and Three) use it, so roaming US phones and travel eSIMs pick it up too.
- The Elizabeth line has coverage end to end, including its tunnels.
- By mid-2026, about 60% of the network's underground stations had coverage, along with growing stretches of tunnel on lines including the Jubilee, Central, Northern, Bakerloo, Metropolitan, Circle and District.
- TfL and Boldyn are aiming to finish the whole network by the end of 2026, after missing an earlier target.
Expect gaps on some lines and between some stations for now. Don't rely on live data to buy a ticket or check directions mid-tunnel; plan your route before you go underground, or save it offline.
Watch out
Phone snatching is a serious problem in London. Thieves on bikes and e-scooters grab phones from people using them at the curb, and pickpockets target phones on crowded platforms. Step back from the road or into a doorway to use your phone, and don't leave it on a café or pub table. See Safety.
Signal in the Highlands, islands and countryside
Cities, towns and main roads have good 4G and growing 5G. Rural Britain is patchier than Americans expect from a small, crowded country, because hills and glens block signal and masts are sparse where few people live. A government-backed program, the Shared Rural Network, has been adding masts in remote areas, but gaps remain.
Where to expect gaps
- Scottish Highlands: long stretches of the North Coast 500, especially in Wester Ross and Sutherland, the Applecross peninsula, single-track roads in the far northwest and many glens have little or no signal. Knoydart has no road and very limited signal. See the Highlands.
- Scottish islands: Skye's main villages have signal, but the coast roads and Cuillin have gaps. The Outer Hebrides, Mull, Islay, Orkney and Shetland are good in towns and patchy elsewhere. See Scottish islands.
- Wales: valleys in Eryri (Snowdonia) and the Cambrian Mountains, and parts of rural mid-Wales. See Wales.
- England: Lake District valleys and fells, Dartmoor and Exmoor, the Yorkshire Dales, Northumberland and parts of Cornwall's coast. See Lake District and Cornwall and Devon.
- Northern Ireland: good overall, with gaps in the Mournes and Sperrins and along parts of the Antrim coast.
How to cope
- Download offline maps for each area in Google Maps or Apple Maps before you set off.
- Save hotel addresses, booking confirmations and ferry tickets as screenshots or PDFs.
- Pick a UK SIM or travel eSIM that uses EE if you're spending a lot of time in remote areas; it generally has the widest rural reach. Ofcom, the UK regulator, has an online coverage checker by postcode.
- Tell someone your route on hill walks and long remote drives, and don't count on signal to call for help. See Outdoors.
- Carry a car charger or power bank; searching for signal drains batteries fast.
Emergencies, 999 and what3words
Dial 999 for police, fire, ambulance, coastguard and mountain rescue. 112 works too. Calls are free from any phone, including a roaming US phone, and a 999 call will connect through any UK network with signal, even if your own network has none.
- For mountain or cave rescue, call 999 and ask for Police, then Mountain Rescue. On the coast, ask for the Coastguard.
- Most smartphones automatically send their location to the 999 service when you call (a system called Advanced Mobile Location), but don't count on it from a foreign phone. Be ready to describe where you are.
- For non-emergency police, call 101. For urgent but non-emergency medical help in England, Scotland and Wales, use NHS 111 by phone or online; 111 can be harder to reach from a roaming US number, so the online service is often easier. See Health.
what3words
The free what3words app divides the world into squares about 10 feet (3 meters) across and gives each a three-word address. Most UK emergency services accept these, which helps on a hillside, a beach or a country lane with no house numbers. Download the app before you need it, open it to find the three words for your spot, and read them out to the call handler. Some services can also text you a link that shows your three-word address without the app. Give a road name, landmark or grid reference too if you can.
Different from home
The UK doesn't use 911, though some phones redirect it. Learn 999. The US Embassy in London can help American citizens in serious trouble; save its number and the address of your nearest consulate. See Safety.
Plugs, voltage and adapters
The UK uses Type G plugs: three thick rectangular prongs in a triangle. Power runs at 230 volts, 50 Hz, about twice the US 120 volts. Ireland uses the same plug; continental Europe doesn't.
What works and what doesn't
- Phones, tablets, laptops and camera chargers: almost all are dual voltage. Look for "Input: 100–240V" on the charger. These need only a plug adapter.
- Hair dryers, flat irons, curling wands, electric toothbrush bases and travel kettles from the US: many are 120 V only and will overheat, burn out or trip the power if plugged in through an adapter. Use dual-voltage models or buy a cheap one in the UK at Boots, Argos or a supermarket for around £15–25 (about $20–33). Most hotels provide a hair dryer.
- Voltage converters are heavy and rarely worth packing. If a device isn't dual voltage, leave it at home.
Adapters
Bring two or three Type G adapters, ideally ones with USB-C and USB-A ports so one socket charges several devices. Compact UK-only adapters are sturdier than bulky universal ones, which can fall out of UK sockets under their own weight. Airports and big stations sell them at a markup; Boots, Argos and supermarkets sell them cheaper.
Different from home
UK sockets have an on/off switch beside them. If your phone isn't charging, check the switch is flipped on (usually down). Bathrooms don't have regular sockets for safety reasons; the two-pin "shavers only" socket by the mirror is for electric razors and toothbrushes, and some offer a 115 V setting. British plugs also contain a fuse, which is normal.
Insider tip
Many hotels, trains and airports now have USB sockets, and most long-distance trains have regular UK sockets at seats. A small power bank covers the rest. Older country hotels and B&Bs can have few sockets per room, so an adapter with several ports helps.
Apps to download before you go
These are the apps Brits actually use. Download them at home on Wi-Fi and sign in before you travel.
Citymapper
The best journey planner for London, and useful in several other UK cities. It compares Tube, bus, bike, walking and ride-hailing, tells you which train car to board for a quick exit, and warns about disruptions.
TfL Go
Transport for London's official app, with a live Tube map, line status, step-free routes and the latest on closures and strikes. Good for checking weekend engineering works.
Trainline
The most popular app for buying UK train tickets, with e-tickets, railcard discounts and split-ticket savings. It adds a small booking fee; train companies' own apps (LNER, Avanti, GWR, ScotRail and others) sell the same fares without one.
National Rail
The official source for live departures, platforms, delays and planned works across Great Britain. Use it on the day to check your train is running; ticket purchases link through to train companies.
Uber, Bolt and FREENOW
Uber and Bolt run in London and most big cities. FREENOW (now owned by Lyft) books licensed black cabs in London and some other cities. In small towns, rural areas and islands, ride-hailing may not exist, so save a local taxi number.
what3words
Gives a precise three-word address for any 10-foot square. Useful for meeting points and for telling 999 exactly where you are in the countryside.
Google Maps or Apple Maps
Both work well for driving, walking and transit across the UK. Download offline areas before rural trips.
Britain's default messaging app. Hosts, guides, drivers and restaurants often use it instead of texts or email.
Also useful
- Parking: RingGo, PayByPhone and JustPark, depending on the council or car park. See Driving.
- Weather and walking: the Met Office app for forecasts, OS Maps for walking routes, and Walkhighlands for Scotland. For mountains, check the Mountain Weather Information Service website.
- Theater and food: TodayTix for West End tickets and lotteries (see London theatre), OpenTable and restaurants' own booking pages, and Too Good To Go for cheap surplus food.
- Railcards: the Railcard app holds digital railcards. See Money and Getting around.
- Regional transport: Translink in Northern Ireland, and ferry operators such as CalMac for Scotland's west coast islands.
Before you fly: phone checklist
- Check what your US plan includes abroad and what it costs per day.
- Ask your carrier to unlock your phone if you plan to use an eSIM or UK SIM.
- Buy and install a travel eSIM at home if that's your plan.
- Turn on Wi-Fi Calling, and know how to turn off data roaming on your US line.
- Add your cards to Apple Pay or Google Pay for the Tube, buses and shops.
- Download Citymapper, TfL Go, Trainline or your train company's app, National Rail, Uber or Bolt, what3words and WhatsApp.
- Save offline maps for rural areas and screenshots of key bookings.
- Pack Type G adapters with USB ports, a power bank and a car charger if you're driving.
- Leave 120 V-only hair tools at home.
- Save 999, the US Embassy number and your travel insurer's emergency line.
Sorting out cards and cash next? See Money and costs. For the overall plan, start with Plan your trip, and check the packing list.
Add it to a route in the trip builder, or ask us to plan the hotels, trains and guides for you.