TL;DRFor a light week (maps and messages), Saily’s 5 GB plan at $12.99 is the cheapest. For most 1 to 2 week trips, Simbye’s 40 GB plan at about $19.96 with our code gives far more data than the unlimited plans for less money. Paying AT&T or Verizon $12 a day costs $84 for a week.
We checked every price below on each provider’s own website on October 18, 2026. No roundup sites, no “from” prices. Where a provider sells in euros, we converted at the European Central Bank rate of 1.1206 dollars per euro (October 9, 2026); your card may add a foreign transaction fee on top (here’s how to avoid that).
The comparison
Simbye is our affiliate partner: if you buy through its link or use the code GATE3615, we earn a commission at no extra cost to you. The other providers in this table pay us nothing.
| Provider | For about a week | For about two weeks | Hotspot | Network |
|---|---|---|---|---|
| Simbye | 40 GB, 30 days €20.95 ($23.48); $19.96 with GATE3615 | 40 GB, 30 days (same plan) $19.96 with code | Allowed | Three |
| Saily | 5 GB, 30 days $12.99 | 10 GB, 30 days $18.99 | Allowed | Not named |
| Airalo | Unlimited, 7 days $27.00 | Unlimited, 15 days $48.00 | Allowed | EE |
| Holafly | Unlimited, 7 days $27.50 | Unlimited, 15 days $51.50 | 1 GB a day | Several UK networks |
And what your US carrier charges instead:
- AT&T International Day Pass: $12 a day for one line ($6 for each extra line that day). Never more than 10 daily fees per line per bill period. A 7 day trip costs $84, a 14 day trip $120.
- Verizon TravelPass: $12 a day per line. 5 GB of high-speed data per TravelPass session, then 3G speeds. A 7 day trip costs $84, a 14 day trip $168.
- T-Mobile Experience plans: Experience More includes up to 5 GB of high-speed data abroad, Experience Beyond up to 15 GB, then 256 kbps. Calls are $0.50 a minute.
Which one to buy
- Light use, one week. Saily 5 GB for $12.99. Simbye does not sell a UK plan smaller than 40 GB, so for maps, messages and the odd photo upload Saily is cheaper.
- Most trips, 1 to 2 weeks. Simbye 40 GB for €20.95, about $19.96 after the GATE3615 code. That is more data than most people use in a month abroad, for less than any unlimited plan here, and it lasts 30 days.
- You want “unlimited”. Airalo at $27 for 7 days is the cheapest unlimited plan we found. Airalo allows hotspot use, but under its fair use policy its unlimited plans slow to 1 Mbps after 3 GB a day, so unless you need more than that on most days, a fixed plan does the same job for less.
- You are on T-Mobile Experience. Your plan already includes 5 GB (More) or 15 GB (Beyond) of high-speed data abroad. If that covers you, you may not need an eSIM at all.
How much data you need depends far more on habits than on the destination. Maps, messaging and photo uploads on hotel WiFi at night fit easily in 5 GB a week. Video calls, streaming on the train and sharing a hotspot with a laptop are what burn through it.
Simbye UK plans in detail
| Plan | Price | In dollars | With GATE3615 |
|---|---|---|---|
| 40 GB, 30 days | €20.95 | $23.48 | $19.96 |
| 100 GB, 30 days | €28.95 | $32.44 | $27.58 |
Prices are from Simbye’s UK eSIM page, which showed a slightly different price at checkout for a few plans in the past. Check the total before you pay.
Calls and texts
Simbye’s UK page lists a +44 number with calls and texts, but its own FAQ says outgoing calls still go over your home SIM. Until that is cleared up, we treat every plan here as data only.
Keep your US line switched on if you need texts from your bank, but know what it triggers. On AT&T, making a call or sending a text from your US number abroad starts the $12 day fee; texts you receive do not. On Verizon, the fee applies on any day you make or receive a call, send a text or use data on the US line. The safest setup: set the travel eSIM as your data line and turn off data roaming on the US line before you land.
Things specific to the UK
One thing that catches people out: since Brexit, the UK is not part of the EU’s roaming rules. A “Europe” eSIM may or may not include the UK, so if you are adding Paris or Amsterdam to a London trip, check the country list before you buy rather than assuming.
London’s buses and the Underground take contactless cards and phones at the gate, so working data matters less for transit there than in most cities. It matters a lot for maps, ride apps and the inevitable “which exit?” moment. Our transit card tip covers the rest.
Before you buy
- Check your phone is unlocked. On an iPhone, Settings, General, About should say “No SIM restrictions”. A carrier-locked phone cannot use another provider’s eSIM.
- Install at home, not at the airport. Every plan here starts its clock when it first connects in the UK, not when you install it. Our eSIM timing tip walks through it.
- Prices change. These were correct on October 18, 2026. Providers run sales often, so a quick look before you buy is worth it.
Bottom line
Do not pay $12 a day to roam in the UK. If you only need maps and messages for a week, Saily’s 5 GB plan is the cheapest option. For anything more, Simbye’s 40 GB plan costs less than every unlimited plan here and lasts a month. Buy it at home, install it on WiFi, and switch it on when you land.
Questions people ask
Do I need an eSIM for the UK if I have T-Mobile?
Not always. T-Mobile Experience More includes up to 5 GB of high-speed data abroad and Experience Beyond up to 15 GB, then 256 kbps. If that is enough for your trip, you can skip the eSIM; if not, a small eSIM is cheaper than a T-Mobile pass.
How much does AT&T or Verizon charge in the UK?
Both charge $12 a day per line as of October 2026. AT&T caps it at 10 daily fees per line per bill period, so a 14 day trip costs $120. Verizon has no such cap in its TravelPass terms, so 14 days costs $168, with 5 GB of high-speed data per session.
Can I keep my US number while using a travel eSIM?
Yes. Keep your US line on for incoming texts and set the travel eSIM as your data line. Making calls or sending texts from the US line can still trigger your carrier's daily roaming fee, so use WhatsApp, FaceTime or iMessage over data instead.
