Roaming, travel eSIM and local SIM compared
Start with your UK tariff. If your destination and expected use fit its allowance, you may not need another SIM. If they do not, compare the whole trip rather than one attractive headline.
Your five options at a glance
- Inclusive allowance: use the part of your UK allowance that your tariff permits in that destination.
- Provider pass or bundle: pay a daily, weekly or fixed charge for a stated amount of roaming use.
- Pay-as-you-go roaming: pay your UK provider’s out-of-bundle rate for each unit of data, calls and texts.
- Travel eSIM: add a separate plan, often for data only, and keep or turn off your home line as needed.
- Local SIM: buy service from a provider in the country you are visiting, which may include a local number if the plan covers calls and texts.
There is no universal winner. Destination coverage, trip length, expected data use, whether you need your UK number and the exact terms of each option decide the result. If you have those figures, the roaming cost checker compares them for one trip.
1. Inclusive allowance
Check this first. An inclusive allowance lets you use some of your existing UK plan in named destinations without buying a separate pass. The important words are “some” and “named”: the roaming data limit can differ from your home allowance, and a nearby country can sit in a different zone.
Do not assume that EU travel is included. Surcharge-free roaming in the EU and EEA is no longer guaranteed for UK customers, so the government advises checking your mobile provider’s current policy before travelling. Read the GOV.UK roaming guidance.
In your tariff terms, confirm the destination, roaming allowance, fair-use limit, excluded services and what happens when the allowance runs out. A plan name from an old contract is not evidence that a new version has the same rules.
2. Provider pass or bundle
A pass or bundle is an add-on from your UK provider. It may cover a day, a set number of days, or a fixed allowance of data, calls and texts. Ofcom says providers may offer daily or weekly charges and bundles for travel; the provider must publish its roaming charges. Check Ofcom’s advice on using a mobile abroad.
Check when the pass starts, what counts as a chargeable day, whether it renews automatically, which destinations it covers, and whether calls or texts are included. Then multiply the charge by the number of chargeable days. A convenient daily figure can become a different decision over a longer trip.
3. Pay-as-you-go roaming
Where your provider permits it, this is the fallback when no inclusive allowance or add-on applies. Your provider charges its published roaming rates for the data, calls and texts you use. It can suit a traveller who needs almost no mobile service, but background data makes the final amount harder to predict.
Before relying on it, record the data unit and rate, call rates in both directions, text rate, spend limit and any usage alerts. Ofcom says providers should send an automatic message on entry to another country explaining applicable charges or limits unless you have opted out. Treat that message as a check, not as the first time you investigate the terms.
4. Travel eSIM
A travel eSIM is a separate digital SIM plan for one country, a region or a group of destinations. Many travel plans provide data but no conventional mobile number. Your UK number does not automatically become part of that plan: calls and texts on the home line remain subject to your UK provider’s roaming terms.
Compare the exact destination coverage, data allowance, validity period, activation rule, network access, tethering policy and fair-use terms. Also check whether the phone supports eSIM and can use the travel provider. Apple’s guidance, for example, says an iPhone must be unlocked to use a different provider and explains how supported models can keep two lines active. Read Apple’s UK travel eSIM guidance.
5. When a local SIM may be better
Put a local SIM on the shortlist when you are staying for longer, need a local number, will make local calls, or need access to a particular local network. It may be a physical SIM or an eSIM. Registration or identity requirements vary by country, and replacing a physical UK SIM means storing it safely until the journey home.
Compare it on the same basis as the other options: full-trip cost, usable coverage, data amount, validity, calls and texts, setup effort and the consequences of losing access to your UK number. A local plan is not automatically the right answer simply because it is sold at the destination.
Pre-flight eSIM and dual-SIM checklist
- Check compatibility. Confirm that your exact phone supports eSIM, is unlocked where required, and can keep the combination of lines you need active. Use the maker’s instructions for iPhone or Google Pixel, rather than instructions for a similar model.
- Install while you have reliable internet. Download and label the eSIM at home or on trusted Wi-Fi, but check whether installing or first connecting starts its validity period. Keep the provider’s setup details available offline.
- Select the data line deliberately. Set the travel eSIM as the mobile-data line and disable automatic data switching or fallback unless you understand how your phone will use it.
- Protect the home SIM. Turn off data roaming for the UK line and verify that the travel line is carrying data. If the travel provider instructs you to enable data roaming for its eSIM, change the setting for that line only.
- Decide what happens to calls and texts. A data-only plan will not replace ordinary calls or SMS. Keeping the UK line active can preserve access to the number, but calls, voicemail and texts may still be charged under the home provider’s roaming terms.
- Recheck destination coverage and terms. Confirm every country on the itinerary, included networks, allowance, expiry, activation point, tethering and any fair-use limit before paying.
Compare the whole trip
Gather the figures from your UK provider and any separate plan you are considering. Our roaming cost checker compares an inclusive allowance, provider pass, pay-as-you-go use and a separate eSIM using the numbers you enter. It does not assume one route wins.
Sources and device guidance reviewed 4 August 2026. Roaming policies, destination lists and phone menus can change, so check the current terms for your tariff, destination and device before travelling.