What a UK eSIM number can and cannot do when you are abroad

Incoming SMS. This is the main job of the line. A text sent to your +44 number reaches the phone as long as the phone has registered on a mobile network in the country you are in. The line needs a cellular signal from a partner network, even though it carries no data of its own.

Incoming calls. Included, with the same condition: the phone has to be registered on a network. Registration is the single point of failure, so a country where the line struggles to register is a country where both texts and calls struggle.

Outgoing calls and outgoing SMS. Not included. You cannot dial from the +44 line or send a text from it. To call someone, use your normal SIM, a local SIM, or a calling app over Wi-Fi.

Mobile data. Not included, in the UK or anywhere else. That surprises people who assume an eSIM always means data. An app that is already set up, such as WhatsApp, runs over whatever internet your phone has from Wi-Fi or another SIM. The +44 number only has to receive a code when the app asks for one.

Whether the line registers in a given country is the question that matters, so we publish buyer reports instead of a promise. As of the latest report in our data, 20 October 2026, there are 736 reports covering 82 countries: 695 saying the line worked and 41 saying it did not. The full table, including countries with a single report, is at /uk-esim-coverage/.

The failures are not spread evenly. Russia has 35 reports of success and 24 of failure. Mainland China has 11 and 6, and Hong Kong 11 and 5. In those three, roaming depends on the local partner network and the region, so treat the line as patchy and do not rely on it for a code you cannot miss. Smaller numbers are not conclusions: Armenia has 6 and 1, Ghana 2 and 1, Thailand 1 and 1, and Iran and Turkmenistan only have failure reports so far (2 and 1). Countries with many successful reports include Germany (57), the United States (53), Peru (43) and Spain (32).

Two cautions. These are what buyers told us, not a measurement we ran, and a country with few reports tells you little either way. And registering on a network is not the same as an app accepting the number: standard SMS verification works, but no provider can promise that a given service accepts a given number. North Korea has no usable UK roaming at all.

Roaming has to be on for the +44 line. The line always registers on a local partner network, so with roaming off the phone can show no signal and receive nothing. On iPhone: Settings, Cellular (Mobile Data), select the +44 line, Data Roaming. On Android: Settings, Network & Internet, SIMs, select the +44 line, Roaming. Menu names shift between versions and brands. Turning roaming on does not give the line data, and it is not charged extra.

Give it time. First registration in some countries can take one to six hours, and retrying does not speed it up. Toggle airplane mode once, restart the phone, and request a code from a second service to tell a problem with the line from a problem with one platform.

Label your lines in the phone settings, for example UK and Home, so you do not switch off the wrong one at an airport.

Wi-Fi covers messaging apps and is also what you need to install the eSIM, since the profile downloads when you scan the QR.

A local SIM bought on arrival gives you a number and data in that country and suits a long stay. Keep the +44 line in the second slot or eSIM profile.

A travel data eSIM adds data without a shop visit. BuyUKeSIM sells prepaid travel data by country and region at /travel-esim/. It is a separate product with its own QR, and unlike the UK number QR it can be reopened from your order page.

The UK + travel bundle at /bundle/ is one crypto payment that delivers two QR codes: the +44 line and a travel data plan. It is optional. Many people buy the +44 line alone and use Wi-Fi.

The UK number QR is single use. It installs once, is never reissued, and UK number orders are not refunded, so check your phone supports eSIM (/compatible-devices/) and install on stable Wi-Fi without interrupting the download. Turn VPN, iCloud Private Relay and Private DNS off while installing, then back on. Travel data eSIMs differ: their QR can be reopened.

The line is from $25 for the first 6 months, and keeping it is a $15 top-up per further 6 months (/topup/). A number that passes its end date is released and cannot be recovered. You pay in crypto and no identity is needed to buy.