Most travel eSIM data expires. You buy 5GB for seven days, use 2GB, and the rest vanishes the moment the clock runs out. eSIM data that never expires solves that by billing you for what you use and leaving the remainder in your account for the next trip. Umi does this with Flow, a pay-as-you-go balance that has no expiry date at all, on one Universal eSIM that covers 200+ destinations.

Quick answer: If you want eSIM data that never expires, choose a pay-as-you-go balance rather than a dated bundle. Umi's Flow balance never expires, draws down only as you use data, and works across 200+ destinations on the same Universal eSIM, so whatever you do not use in Lisbon is still there for Tokyo.

Do eSIMs expire?

Usually, yes, but "expires" can mean three different things, and the difference matters. The eSIM profile itself, the data bundle you bought, and any credit sitting in your account can each have their own expiry rules. Most complaints about eSIM data expiring are really about the second one: a bundle with a validity window that ends whether you used the data or not.

Here is how the three play out with a typical travel eSIM and with Umi:

So the honest answer is that Umi's Plans do have a validity period, like any prepaid bundle, but the Flow balance underneath them does not. That balance is the part that never expires, and it is the part this guide is about. For the basics of how an eSIM works, GSMA's eSIM explainer covers the technology, and MoneySavingExpert has a plain-English guide to what an eSIM is for UK travellers.

Which eSIM offers data that does not expire?

Umi offers it through Flow: you top up a balance in the app, data is deducted as you use it, and anything left over stays in your account with no expiry date. A handful of other providers sell "lifetime" or long-validity bundles, but most travel eSIMs still sell dated packages, so check the small print for a validity window before you assume the data is safe.

The practical difference shows up on your second trip. With a dated bundle, every trip starts from zero and every trip ends with waste. With a Flow balance, a long weekend in Paris might use 2GB of a 5GB top-up, and the remaining 3GB is waiting when you fly to Bangkok in March. Nothing to rebuy, nothing to reinstall, and no new eSIM per country, because the same Universal eSIM covers both. If you are weighing Umi against the field, our guide to the best travel eSIM walks through the selection criteria.

How does a pay-as-you-go eSIM balance actually work?

A pay-as-you-go eSIM balance works like a prepaid wallet. You add money, your data use is metered at a per-GB rate for the country you are in, and the cost comes off the balance as you go. There is no bundle to pick in advance and no date by which you must use it up.

With Umi, the steps are short:

1. Install your Universal eSIM once, which takes under 60 seconds in the app.

2. Top up a Flow balance with whatever amount suits you.

3. Land, switch on data roaming for the Umi line, and use data. The app shows what is left.

4. Fly home, or on to the next country. The balance stays put until you next need it.

Because the balance is just money, not a country-specific bundle, it follows you across 200+ destinations at that destination's rate. That is also why a pay-as-you-go balance suits irregular travellers so well: two trips a year, a few GB each, and no bundle ever bought for a trip that got cancelled. For the wider comparison of providers, see our round-up of pay-as-you-go eSIM options.

What does eSIM data that never expires cost?

Umi's Flow rate is from $2.55/GB on many destinations, and the balance you buy it with never expires. Fixed Plans work out cheaper per GB on the same destination, but they carry a validity window, so the right choice depends on whether you will use the data inside that window.

These are live rates from the Umi destination pages on 23 September 2026. They change, so the destination page is always the source of truth.

All prices in USD. Japan rates were checked on 1 September 2026.

Read the table by usage, not by headline. A 20GB Plan for the United States is the cheapest data per GB in that row, but only if you will use most of 20GB inside the validity window. If you use 6GB, you paid $30.55 for 6GB, which is over $5 per GB. The same 6GB on Flow costs $15.30, and the balance you did not touch is still yours. Plans win for one heavy trip; Flow wins for light, irregular, or multi-country travel, and for anyone who hates paying for data they never use. Neither model is cheapest in every case, and we would rather you pick the right one.

Is unlimited eSIM data really unlimited?

No. Every "unlimited" travel eSIM plan on the market applies a fair-use cap, usually somewhere around 1GB to 3GB per day, and throttles your speed once you pass it. Unlimited means you will not be cut off, not that you get uncapped full-speed data. Those plans are also dated, so the "unlimited" allowance still expires when the plan does.

Umi does not sell an unlimited data plan, and that is deliberate. You get premium 4G/5G that is never throttled, and you pay for the data you use from a balance that never expires. The one thing Umi does call unlimited is hotspot and tethering: there is no separate cap on sharing your connection to a laptop or a companion's phone. That sharing still draws from your Flow balance or Plan, so it is unlimited sharing, not unlimited data. If you mainly want a big daily allowance for streaming on one short trip, a throttled unlimited plan from another provider can suit you. If you want speed and no waste, a never-expiring balance is the better fit.

Is there a yearly eSIM plan available?

You do not need a yearly plan to keep data for a year. A Flow balance already does that, because it has no expiry at all, so it covers a year, or three, without a subscription. Umi has no annual data plan and no recurring fee for consumers; you top up when you want and stop when you want.

For teams it is slightly different. Umi Business gives an organisation one shared pay-as-you-go balance, priced from $19.95 per user per year, with admin controls and the ability to distribute Plans to travelling staff. That is a team product, not a family plan. Individuals and families are best served by a personal Flow balance, which costs nothing to hold and only costs money when you use data.

What are the disadvantages of eSIM data that never expires?

The main trade-off is price per GB. A never-expiring balance is metered at the Flow rate, which is higher per GB than a large fixed Plan you use in full. If you know you will burn through 20GB in a fortnight, a Plan is cheaper. There are also the general limits of any eSIM: your phone must support it, and Umi is data-only, so calls run through apps like WhatsApp, with voice and SMS coming soon.

None of those are unique to no-expiry data, and Umi lets you mix the two models. Add a Plan for the heavy trip, keep a Flow balance underneath as the fallback, and the Plan takes priority while it is active. When the Plan ends, you fall back to Flow rather than to no signal. That combination is hard to find elsewhere, and it is the reason the never-expiring balance is a safety net as much as a saving. To keep a balance topped up while abroad, our eSIM top-up guide covers the steps.

What is the best way to get data with no expiry?

The best way to get data with no expiry is a pay-as-you-go eSIM balance on an eSIM you keep, rather than a dated bundle on a throwaway profile. Umi's Universal eSIM plus a Flow balance gives you both: install once, top up once, and let the balance carry from trip to trip across 200+ destinations at premium 4G/5G speeds.

The test is simple. If the data you buy today is still yours in a year, on a different continent, on the same eSIM, it never expires. That is what Flow does, and it is why light and multi-country travellers tend to stick with it. Ready to stop losing data at the end of every trip? Install your Universal eSIM and top up your Flow balance before you fly.