You are somewhere unfamiliar, the map stops loading, and the phone says you have no data. It is a bad five minutes. It is also, in almost every case, about sixty seconds from being fixed, on the eSIM already in your phone, with nothing to reinstall. The fix has one precondition, and checking it takes five seconds. Everything else in this guide follows from what that check says. So: what to look at first, how to add data to the eSIM you already have, the part almost nobody knows about what that does to your expiry date, the two cases where the easy route is closed, and how to see either of them coming.
Before anything else, look at the days remaining
Open your dashboard, find the eSIM, and read the days remaining on it. That one number decides which of two completely different situations you are in, and it takes five seconds.
If there are days left, you are in the easy case, and the rest of this guide is about a purchase that takes a minute. Your eSIM is not broken and it is not finished. It is empty, which is a different thing, and empty is refillable. This is why an eSIM at zero data stays in your active list rather than dropping into your history: it is still a working eSIM waiting to be filled.
If the days are gone, you are in the hard case, and no amount of buying data will help, because there is no longer a live plan to attach it to. What you need is a new eSIM, and the second half of this guide covers how to recognise that situation and what it costs you.
Almost everyone assumes running out of data is the serious problem and running out of days is an administrative detail. It is the other way round. Data is the recoverable one. That single inversion is the most useful thing on this page, and it is why the number to read first is the calendar, not the gigabytes.
- Days remaining is the number that decides everything. Read it first.
- Days left means refillable: same eSIM, about a minute, nothing to reinstall
- No days left means a new eSIM, because there is no live plan to add data to
- An eSIM at zero data stays in your active list precisely because it can still be filled
- Counterintuitive but true: running out of data is the recoverable problem, running out of days is not
What actually happens the moment the data runs out
Nothing dramatic, and nothing expensive. The data simply stops. Pages stop loading, maps stop updating, and messages sit unsent until you find a connection. The eSIM stays installed on your phone, the line stays in your settings, and nothing gets billed.
That last part is worth dwelling on, because it is the real difference between a travel eSIM and roaming on your home contract. There is no overage rate here. You cannot run up a bill by continuing to use a plan that has run out, because there is nothing left to use. The connection just stops, which is inconvenient and finite, rather than convenient and open ended.
On our side, the eSIM changes to a depleted state and you get told about it. It stays visible in your active eSIMs, with a top-up button on it, because as long as its days have not run out it is still a working eSIM that happens to be empty.
What you should not do is delete the eSIM from your phone. It is the natural instinct when something has stopped working, and it is the wrong move: the profile in your phone is what a top-up refills. Delete it and you have thrown away the thing you were about to fix.
- Data stops. Nothing is billed, and there is no overage rate to run up.
- The eSIM stays installed and stays in your active list, because it can still be refilled
- You get a notification when it happens, by push and by email
- Do not delete the profile from your phone. That is the thing a top-up refills.
How to add more data to the eSIM you already have
The whole process runs on the eSIM already in your phone. There is no new QR code, no second install, and no new line appearing in your settings. You are refilling the one that is there.
Open your dashboard and find the eSIM in your active list. If its days have not run out, it carries a top-up button. Tap it and you get a list of the plans available for that destination, cheapest first. Pick a size, pay, and the data lands on the same eSIM. It usually takes under a minute, and the phone picks it up without you doing anything.
If you are not logged in, which happens a lot when you are abroad and cannot remember a password, the out-of-data email we send carries a direct link to the top-up page for that specific eSIM. It works without signing in. That link exists precisely because the moment you need it is the moment you are least able to go hunting for credentials.
One genuine catch deserves saying out loud, because no amount of good design gets around it: buying a top-up needs an internet connection, and you have just run out of one. In practice you use whatever is around, which is nearly always the hotel or café wireless, the airport network, or a travelling companion’s hotspot for the sixty seconds it takes. It is worth knowing in advance rather than discovering it at a bus stop.
- Dashboard, find the eSIM, tap top up, pick a size, pay. Under a minute.
- No new QR code, no reinstall, no second line in your settings
- Not logged in? The out-of-data email links straight to the top-up page for that eSIM
- You need some connection to buy: hotel or café wireless, the airport network, or a companion’s hotspot
The part most people do not know: a top-up buys days as well as data
Almost everyone assumes a top-up just refills the bucket. It does more than that, and the extra part is genuinely valuable.
When you add a plan to an existing eSIM, its validity is added to what you already have rather than replacing it. The new days stack on top of your current expiry date, not from the day you bought them. So if you have twelve days left and you top up with a thirty-day plan, you end up with roughly forty-two days, not thirty.
This changes the arithmetic of a decision people get wrong. Faced with running low, the instinct is often to buy a second eSIM for the same country. That gives you a separate plan on a separate clock that you have to install separately. Topping up instead gives you the data, extends the window on the eSIM already working in your phone, and costs the same as buying that plan would have.
It also means the expiry warnings reset. Because the top-up moves the expiry date, the notifications that count down to it start counting to the new date instead. You are not left with alarms tied to a deadline that no longer applies.
- Added days stack on your existing expiry, they do not replace it
- Twelve days left plus a thirty-day top-up is about forty-two days, not thirty
- Same price as buying that plan on its own, so the extra validity is free
- The expiry warnings re-point at the new date automatically
You are not locked into the size you originally bought
A common assumption is that topping up means buying the same plan again. It does not. What you get offered is the range of plans available for that destination, sorted cheapest first, and you can take any of them.
That flexibility is worth using rather than ignoring. Someone who bought a small plan for a short trip and then had it extended by a delayed flight can add the smallest option to bridge a couple of days. Someone who badly underestimated and is on day three of fourteen can jump to a much bigger size and stop thinking about it.
There is one rule about what appears in that list. Unlimited eSIMs are extended with unlimited options and fixed-data eSIMs are topped up with fixed-data plans, because the two work differently underneath. You will not be offered a mix, so there is nothing to get wrong.
The list is also filtered to your eSIM’s own destination. A plan bought for one country tops up with plans for that country, and a regional plan tops up with plans on that region. If your trip has genuinely moved on to somewhere your current eSIM does not cover, that is a new eSIM rather than a top-up, and the coverage list on the destination page is where to check.
- You get the full range for that destination, cheapest first, not a repeat of what you bought
- Top up small to bridge a delay, or jump up a size if you underestimated
- Unlimited extends with unlimited; fixed data tops up with fixed data
- Moved to a country your eSIM does not cover? That is a new eSIM, not a top-up
The first case where you cannot top up: single-day plans
Nearly every plan we sell can be topped up. Of the roughly two thousand active plans in our range, around nine in ten accept a top-up. The exceptions are worth knowing because they cluster in one place.
Almost all of them are the single-day plans. These are sold as one self-contained day of data, and that shape does not accept additions once it is running. When one runs out it is finished, and the answer is to buy another plan rather than extend that one.
We do not hide this until checkout. On an eSIM that cannot be topped up, the dashboard shows a plain message where the top-up button would normally be, so you find out by looking rather than by trying and failing. That is deliberate: the worst moment to discover a limitation is the moment you are relying on it not existing.
The practical advice is to think about this before you buy rather than after. Single-day plans look efficient for a short trip, but they are the one shape with no safety net, and on most destinations a fixed plan with a longer window costs surprisingly little more while remaining refillable throughout. If you are the kind of traveller whose plans change, that difference matters more than the sticker price.
- Around nine in ten of our active plans accept a top-up
- The exceptions are almost entirely the single-day plans
- The dashboard tells you before you try, in place of the top-up button
- For a trip that might change shape, a refillable plan with a longer window is the safer buy
The second case: the window has already closed
The other situation where topping up is unavailable is the one people find more surprising, because the eSIM looks perfectly healthy. Its validity window has ended.
Once the days run out, the plan behind the eSIM is finished, and there is nothing left to add data to. The top-up button disappears and the eSIM moves out of your active list into your history. This is not a policy decision on our part, it is what the plan reaching its end date means.
The trap is that this can happen while you still have data left. Someone who bought a generous plan for a two-week trip and used very little of it can reach the end of the window with gigabytes unspent, and none of it carries over. Data does not survive the expiry of the window it was sold in.
Which is the argument for buying the validity window you need rather than the smallest one that looks sufficient. On most destinations, moving from a short window to a monthly one costs very little, and it converts a hard deadline into a comfortable margin. It also means that if the trip extends, you are topping up rather than starting again.
- When the days run out the plan is finished, and the top-up route closes with it
- This can happen with data still unused, and unused data does not carry over
- The eSIM moves from your active list to your history at that point
- Buying a longer window up front is usually cheap and turns a deadline into a margin
The warnings you get before either clock runs out
Neither of these should ever be a surprise, and we put real effort into making sure it is not. You get told as both clocks run down, by push notification and by email, in whatever language your account is set to.
On the data side, the alerts come as you pass half your allowance, then eighty percent, then ninety percent, and then again at the moment you actually run out. That last one exists because for a long time the final signal anyone got was ninety percent, and being told you are nearly out is not the same as being told you are out.
On the validity side, you get warnings at seven days, three days and one day before the window closes, and again when it has. Those are the ones worth reading carefully, because that is the deadline you cannot negotiate with afterwards.
What to do with each is simple enough. At eighty or ninety percent of your data, with plenty of days left, decide whether the rest of the trip needs more and top up at your leisure on the hotel wireless. At seven days, look at how much data you have left and whether the trip actually ends before the window does. At one day, if the trip is continuing, top up now while the button is still there.
- Data alerts at half your allowance, eighty percent, ninety percent, and at zero
- Validity alerts at seven days, three days, one day, and at expiry
- Both arrive as push and email, in your account’s language
- The seven-day warning is the important one, because after expiry there is nothing to top up
Top up, or buy a new eSIM?
When both routes are open, topping up is almost always the better one. It costs the same as buying that plan by itself, it lands on the eSIM already working in your phone, it needs no installation, and it pushes your expiry date out rather than starting a second clock alongside the first.
Buying a new eSIM is the right answer in three situations, and they are easy to recognise. The window on your current eSIM has closed. The plan you bought was a single-day one that cannot be extended. Or your trip has moved to a country your current eSIM does not cover, in which case what you need is different coverage, not more data.
There is a fourth case that is more of a judgement call. If you are near the end of a trip and only need a small amount to get home, the cheapest small plan for that destination bought as a top-up is usually the tidiest answer, because it also buys you the days. Starting a whole new eSIM for the last afternoon of a holiday is effort you do not need to spend.
And if you are reading this before you travel rather than during, the whole thing reduces to one decision made at purchase: buy a refillable plan with a window comfortably longer than your trip. That single choice is what keeps the easy fix available for the entire time you are away.
- Top up when the window is open: same price, same eSIM, no install, and it extends your days
- Buy new when the window has closed, when the plan was a single-day one, or when you have moved outside your coverage
- Near the end of a trip, a small top-up beats a whole new eSIM
- Before you travel, the decision that matters is a refillable plan with a window longer than the trip
Frequently asked questions
What happens when my travel eSIM runs out of data?
The data stops and nothing else happens. There is no overage charge, no automatic renewal and no bill, because a travel eSIM cannot be used past what you bought. The eSIM stays installed on your phone and stays in your active list, because as long as its validity window is still open you can add more data to it. The one thing not to do is delete the profile from your phone, since that is exactly what a top-up refills.
How do I top up my eSIM?
Open your dashboard, find the eSIM in your active list, and tap the top-up button on it. You get the plans available for that destination, cheapest first. Pick a size, pay, and the data lands on the same eSIM, usually in under a minute. There is no new QR code and nothing to reinstall. If you are not logged in, the out-of-data email we send links straight to the top-up page for that specific eSIM.
Can I top up an eSIM that has already run out of data?
Yes, and that is the normal case. An eSIM at zero data is not finished, it is empty, and it stays in your active list with its top-up button for exactly that reason. The only thing that closes the option is the validity window ending. So if you have run out of data but still have days on the clock, you are fine.
Does topping up extend my eSIM’s validity?
Yes, and this is the part most people do not expect. The days from the plan you add stack on top of your current expiry date rather than replacing it or starting from today. Top up with a thirty-day plan when you have twelve days left and you end up with about forty-two days. The expiry warnings automatically re-point at the new date.
How do I top up if I have no data to get online with?
You need some connection to make the purchase, which is the genuine catch. In practice people use hotel or café wireless, the airport network, or a travelling companion’s hotspot for the minute it takes. Your eSIM stays installed throughout, so once the top-up goes through the phone picks it up on its own. It is worth knowing this in advance rather than working it out at a bus stop.
Can I top up with a different amount than I originally bought?
Yes. You are shown the full range of plans for that destination, sorted cheapest first, and you can take any of them. Add the smallest option to bridge a delayed flight, or jump to a much larger one if you underestimated at the start. The only rule is that unlimited eSIMs are extended with unlimited options and fixed-data eSIMs are topped up with fixed-data plans, because the two work differently underneath.
Why is there no top-up button on my eSIM?
One of three things. The eSIM has not been installed and switched on yet, in which case the button you want is the one that installs it. Its validity window has closed, and once the days run out there is nothing left to add data to. Or the plan is a single-day one, which cannot be topped up, and in that case the dashboard shows a message saying so where the button would normally be.
Can I top up an expired eSIM?
No. When the validity window ends the plan behind the eSIM is finished, the top-up option disappears and the eSIM moves into your order history. There is no way to revive it, so if your trip is continuing the answer is a new eSIM. This is the reason the seven, three and one day expiry warnings are worth reading: they are the last chance to extend cheaply.
What happens to my unused data when the eSIM expires?
It ends with the window and does not carry over to a new plan. This catches people who buy generously for a two-week trip, use very little, and reach the end of the window with gigabytes unspent. It is the main argument for choosing the validity window you actually need rather than the largest amount of data, since on most destinations a longer window costs very little.
Does topping up cost more than buying a new eSIM?
No, it costs the same as buying that plan on its own, so the extra validity a top-up gives you is effectively free. Topping up is also less work: it lands on the eSIM already running in your phone with no second installation and no second line in your settings. When both routes are open, topping up is the better one.
Will I be charged automatically when my data runs out?
No. Nothing renews by itself and nothing is charged without you choosing to buy it. A travel eSIM is a one-off purchase of a fixed amount of data for a fixed window, and when either runs out the connection simply stops. That is the whole reason there is no bill shock with a travel eSIM the way there can be with roaming.
Do I have to reinstall my eSIM after topping up?
No. A top-up refills the profile already on your phone, so there is no new QR code, no second install and no extra line in your settings. The phone usually picks up the new data on its own within a minute. If it seems slow, toggling airplane mode on and off gives it a nudge.
Will I get a warning before my eSIM runs out?
Yes, on both clocks. For data you are alerted as you pass half your allowance, then eighty percent, then ninety, and again at the moment you actually run out. For validity you get warnings at seven days, three days and one day before the window closes. All of them arrive by push notification and email, in whatever language your account is set to.
Should I top up or buy a new eSIM?
Top up whenever the option is there, because it is the same price, needs no installation and extends your expiry date as well as your data. Buy a new eSIM in three cases: the validity window has already closed, the plan was a single-day one that cannot be extended, or your trip has moved to a country your current eSIM does not cover. That last one is a coverage problem rather than a data problem.