eSIM vs roaming: the honest comparison.
We sell eSIMs, so we'll tell you exactly when roaming wins too.
We'd love to tell you eSIMs are always better. That's not quite true. The honest answer depends on where you're from, where you're going, and how much data you use. Here's the real breakdown — including the cases where your phone carrier's roaming deal beats us.
When roaming genuinely wins
If you're a UK resident travelling within the EU or EEA, your carrier likely includes free roaming as part of your plan (check — some have reintroduced charges post-Brexit, others haven't). If yours does include free EU roaming with a generous data allowance, there's no reason to buy an eSIM for a trip to France or Spain. Similarly, if you're on a US carrier like T-Mobile with international data included, short trips to Canada or Mexico may be covered already.
- UK residents: check your carrier app before buying anything. EE, O2, Vodafone, and Three all have EU roaming — but terms change, so verify your current plan.
- US residents: T-Mobile Magenta and above includes data in 210+ countries (throttled speed).
- Australia: Telstra and Optus offer international day passes. Worth checking for short trips.
- If roaming is included in your plan at no extra cost — use it. Don't spend money you don't need to.
When eSIM wins
Outside your carrier's roaming coverage, the maths shifts sharply. Carrier roaming rates to non-included countries can typically reach £5–10 per day, or £10–20 per GB (check your tariff — rates vary). A 5 GB eSIM plan for Thailand costs around £4. A week of roaming to Thailand on a standard UK carrier plan with no roaming inclusion: potentially £50–100+. The gap is real, it's significant, and it adds up fast.
- Asia, Middle East, Latin America, Africa: roaming charges are almost always punishing. eSIM wins clearly.
- USA from the UK: some carriers charge £2–5/day for roaming. A US eSIM for two weeks costs around £6–10 total.
- Canada, Australia, Japan: similar story — eSIM is materially cheaper for trips longer than a day or two.
Hidden roaming costs nobody talks about
Even when roaming is 'included', there are gotchas. Data speeds are often throttled to 3G or slower on roaming (check the small print). Fair Use Policies cap the data you can use abroad — often 12–25 GB per month, sometimes less. Some carriers have reintroduced charges for EU roaming after Brexit. And if you accidentally roam onto a non-partner network, standard rates apply immediately. eSIM plans have no hidden surprises: you buy X GB for Y days, you use it, done.
The real reason people choose eSIM
It's not always about the maths. Many travellers choose eSIM because they want predictability — they know exactly what they're spending before they go. No bill shock. No checking whether their carrier covers this country. No frantic texting support from an airport lounge. You buy your eSIM, it arrives, it works. That peace of mind has a value that doesn't show up in a price comparison.
Quick comparison
A rough guide for common scenarios, based on typical published roaming tariffs. Carrier terms change often, so check yours before you travel:
- UK → EU (2 weeks): Roaming likely free if included. eSIM ~£4–8. Check your plan first.
- UK → USA (2 weeks): Roaming £15–50+. eSIM ~£6–10. eSIM wins.
- UK → Japan (1 week): Roaming £30–70+. eSIM ~£4–6. eSIM wins clearly.
- UK → Thailand (2 weeks): Roaming £50–100+. eSIM ~£4–8. eSIM wins clearly.