← Part of the United Kingdom money guide
Staying connected in the UK.
The UK is easy: coverage is excellent almost everywhere, including on the Underground now. The only real decision is how you pay for data, and for most US travelers an eSIM is far cheaper than the carrier day pass. Here is the math.
At a glance
Coverage
Excellent, cities and countryside
Carrier roaming
About $12 a day
Cheapest
A travel eSIM, a few $ per GB
The Tube
Now has coverage on most lines
Coverage is excellent, so this is really a cost question. Your US carrier will charge about 12 dollars a day to roam in the UK (AT&T and Verizon day passes), which adds up fast, and T-Mobile's included roaming is often slow 2G, fine for messages but not maps. A Nomad eSIM is a few dollars per gigabyte, activates before you fly and works from landing, so for a data-first trip it is the cheapest option. The London Underground now has mobile signal on most lines. Never roam pay-per-use, which runs about 2 dollars a megabyte.
It is a cost question, not a coverage one
The UK has some of the best mobile coverage anywhere, so you will have fast service in cities, towns and most of the countryside whatever you use. That makes this a money decision. The default, roaming on your US plan, is the expensive way: AT&T and Verizon charge about 12 dollars a day to use your plan in the UK, so a week is around 84 dollars before you have done anything special.
T-Mobile and some Google Fi and Visible plans include roaming, but often at slow 2G-style speeds (around 256 Kbps) that are usable for WhatsApp and email but frustrating for maps, rideshare or anything with video. Check your plan's fine print: included does not always mean fast.
Why an eSIM is usually cheapest
For most US visitors, a travel eSIM is the cheapest way to get real data in the UK. A Nomad eSIM is a few dollars per gigabyte, far below stacking up day-pass fees, and it activates before you fly and works the moment you land, with no SIM counter. You keep your US number reachable for calls and texts on your normal plan while the eSIM carries the data.
Coverage is not the deciding factor: a Nomad eSIM rides a major UK network, and since the big networks blanket the country, the brand barely matters here. Set it up before departure, since installing it needs a connection.
The Tube, and one Brexit footnote
Good news underground: the London Underground now has mobile coverage on most lines, rolled out across recent years, so you are no longer offline between stations on the major routes. Aboveground, buses, trains and stations are all well covered, and free Wi-Fi is common in cafes and on much of the transport network.
One footnote that does not affect you: since Brexit, some UK networks charge their own customers to roam in the EU, but that is a UK resident issue, not a US visitor one, so ignore it. For paying as you go, see cash or card in the UK, and the UK money guide.
If an eSIM is the cheaper, simpler call for United Kingdom, Nomad covers it.
Get your Nomad eSIM for United Kingdom(opens in a new tab)we may earn a commissionCommon questions
Quick answers.
Do I need an eSIM for the UK?
For most US travelers it is the cheapest way to get real data. UK coverage is excellent everywhere, so it is a cost question: a Nomad eSIM is a few dollars per gigabyte, versus about 12 dollars a day for an AT&T or Verizon roaming pass. Set it up before you fly and it works from landing.
How much does it cost to use my US phone in the UK?
About 12 dollars a day on an AT&T or Verizon day pass, so roughly 84 dollars for a week. T-Mobile and some other plans include roaming but often at slow 2G speeds. Never roam with no plan, since pay-per-use runs about 2 dollars a megabyte, which is bill-shock territory.
Does my phone work on the London Underground?
Yes, on most lines now. The Underground has rolled out mobile coverage across recent years, so you are no longer offline between stations on the major routes. Aboveground coverage is excellent, and free Wi-Fi is widely available on transport and in cafes.
Is an eSIM or a local SIM better for the UK?
An eSIM is simpler for most visitors: no SIM counter, and it works from the moment you land if you set it up beforehand. A physical UK SIM can be marginally cheaper for very heavy, long-stay data use, but for a normal trip the convenience of a Nomad eSIM wins, and coverage is excellent either way.
More on United Kingdom
The little money things nobody warns you about.
- Tipping in the UKThe UK tips more than most of Europe but far less than the US. The main thing to watch is the discretionary service charge already on restaurant bills, which is optional. Here is what you actually owe.
- Do US citizens need an ETA for the UK?Short answer: yes, now you do, and it even applies to a layover. The UK ETA is not a visa, and it is quick and cheap, but only from the official source. Here is what it costs and how to get it right.
- Do I need cash in the UK, or can I use cards?Short answer: you can do the whole trip without cash. Contactless runs everything, including all of London's transport, and many places no longer take notes at all. Here is how to pay, and the couple of things to get right.
- Bringing your dog or cat to Great Britain.Compared with Japan or Australia, the UK is quick: the lead time is weeks, not months, because there is no rabies blood test for pets coming from the US. The cost surprise is the flight, since pets almost always travel as cargo into Britain, not in the cabin. Here is the order, the official route, and what to budget.
- Can tourists get a VAT refund in the UK?Short answer: no, not in England, Scotland or Wales. This is the opposite of what most European trips teach you, and it catches shoppers out at Heathrow. Here is what changed, and the only two ways left to shop tax-free.
- London taxis, Uber, and the Heathrow transfer.London gives you real choice: a hailable black cab or a pre-booked Uber. But the money is made or lost on the airport run, where the train quietly beats a cab by fifty pounds or more. Here is how it all compares.
Sources, and how this was checked
Last checkedJul 2026
- US Department of StateUnited Kingdom country information and local conditions
- Tom's Guidea 2026 comparison of US carrier international roaming plans and day-pass prices
Our own readCarrier prices and inclusions change with your exact plan, so treat the day-pass figures as a July 2026 snapshot and check your own plan. The steady points are that UK coverage is excellent (including on most of the Underground), that a day pass is the pricey default, and that pay-per-use roaming is punishing.