Local UK SIM or travel eSIM? The numbers, not the marketing

The one fact that decides this

The UK sells prepaid SIM cards with no ID requirement at all. No passport, no registration form, no waiting. They are stocked at Heathrow in every terminal, in Boots, WHSmith, Sainsbury's, Tesco, corner newsagents and every carrier store, and the PAYG bundles from giffgaff and Smarty run about £5–10 for 5–10GB.

That is roughly £1 per gigabyte, and it is cheaper than any travel eSIM sold for the UK. Converted at any recent exchange rate, a £10 bundle with 10GB beats the cheapest verified 10GB eSIM in our data, which is Saily at $18.99 for 30 days.

So unlike most countries, the UK comparison is not close on price. What the eSIM sells you here is the removal of an errand, and for a lot of travellers that is worth paying for. It is just worth knowing that is what you are buying.

The eSIM prices, verified where we could

These rows were read from the providers' own sites on 13 August 2026:

Saily and Airalo track each other almost exactly at every size, which makes the choice between them a matter of app preference rather than value.

Airalo's rows above are all from Uki Mobile, which is one of two UK packages it sells. The other is Uki Mobile+, and it carries the same allowances for more money: $14.00 for 5GB over 30 days against $13.00, $23.50 for 10GB over 30 days against $19.00, and $54.00 for 50GB over 30 days against $39.00. All of those are verified. Airalo does not state what the plus package adds, so we cannot tell you what the extra buys — but the names are on the listings, and against Saily it is Uki Mobile, not Uki Mobile+, that is line-for-line competitive.

Nomad's UK prices have since been read at source: $17.50 for 10GB over 30 days and $25 for 20GB, both below Airalo and Saily. The rows still indicative — figures we hold but have not checked on the sellers' sites — put Holafly at $6.90 for a single day of unlimited data rising to $27.30 for a week. We also hold an eSIM Go row at $14 for 10GB over 30 days, which earlier versions of this page called the best fixed-data value on the list. It is not on the list at all now: eSIM Go sells wholesale to resellers and publishes no consumer price — checked on esim-go.com on 18 August 2026, where there is no basket, no checkout and no per-country page — so its rows cannot be bought or ever verified. See our eSIM Go page.

Where each option actually wins

A local SIM wins on price for any stay of a week or more, gives you a UK number, and is the right answer if you are travelling into rural Britain, where an EE-based plan buys you the widest reach.

A travel eSIM wins when you land already connected — no shop, no queue, no unfamiliar checkout in a currency you have not got yet — and for trips of a few days where the price gap amounts to a couple of pounds. It also wins if the UK is one leg of a multi-country trip, where a regional plan avoids buying SIMs twice.

Unlimited plans are the awkward middle. Holafly's daily rate makes sense only for very short, very heavy usage, and Holafly does not support hotspot — if you tether a laptop, rule it out immediately.

Coverage: EE, then everyone else

EE has 99.8% 4G population coverage and 77.4% 5G availability, the best Opensignal ratings of the four networks, and average speeds of 52.8 Mbps on 4G and 168.4 Mbps on 5G. An eSIM on EE gives you the best geographic coverage for London plus regional travel. O2 is a strong second at 99% 4G. In central London and the big cities all four networks are excellent and the distinction stops mattering.

Where it does matter: the Scottish Highlands and islands, and the Outer Hebrides, Orkney and Shetland in particular. Rural Wales. The North York Moors. Parts of Cornwall. Remote Lake District valleys. And inner-city building interiors — old stone churches and anything underground.

That list is the argument for EE, and for downloading offline maps whatever you buy.

Verdict by trip

Three days in London: travel eSIM, 1–3GB, installed before you fly. Two weeks anywhere: local PAYG SIM from a supermarket, and pocket the difference. Driving in the Highlands or rural Wales: a local EE SIM, because coverage beats price when there is no signal at all. Tethering a laptop: anything except Holafly.

Every plan we track for the UK, provider by provider, is on the UK hub.