You have been there. A two-week trip to Southeast Asia, a 10 GB plan that felt about right, and then a return flight where your data balance still shows 5.2 GB. You land. The plan expires. Those gigabytes disappear without ceremony.

The travel eSIM unused data refund question is one almost nobody asks before buying, and one almost every frequent traveller regrets not asking sooner. A 10 GB plan for a popular Asian destination can cost anywhere from €20 to €45, depending on the provider. If you consumed half of it, you effectively paid double the per-GB rate you thought you were getting. Providers do not advertise this dynamic, but it is baked into their business model. Overselling data that never gets used is quietly profitable.

This problem compounds for frequent travellers. Eight or ten trips a year, a few gigabytes lost on each one: that is a meaningful sum by December. The question worth asking is not just "which eSIM has the best coverage?" but "what happens to my data when I do not use it all?"

Short answer: they do not.

Airalo is the largest eSIM marketplace globally, with plans from hundreds of local operators. Its model is transactional and straightforward. Once your plan expires or your data runs out, that is the end. There is no credit back, no rollover, no compensation for unused gigabytes. Airalo does have an Airmoney loyalty system, but it rewards referrals and select promotions, not unused data at plan expiry. Airalo confirms this directly in their support documentation: unused data simply expires.

Holafly operates primarily on unlimited daily plans, so the travel eSIM unused data refund question is framed differently there. You pay per day of access, not per gigabyte. In theory, you cannot run out of data mid-day. In practice, Holafly applies speed throttling after a daily threshold, though it does not clearly communicate what that threshold is. If you buy a seven-day plan and cut your trip short, you do not get a refund for the unused days, as their own FAQ confirms. For travellers on longer trips who are not consuming data heavily, this model can work out significantly more expensive than a standard fixed-data package. You end up paying for daily access whether you are actively connected or not.

Nomad sells fixed-data plans with clear GB allowances. Like Airalo, once your plan window closes, unused data expires with it. There is no cashback, no Koins equivalent, no rollover to a future trip. Nomad addresses this directly on their blog: the data is simply gone.

None of these providers have a published mechanism for compensating you when you use less than you paid for.

Stop and do the math. Three trips a year, 10 GB each, half unused on average. That is roughly 15 GB of data you paid for and never consumed. At €3 per GB, that is €45 walking straight into a provider's pocket every year, for nothing.

Frequency makes this worse, not better.

Kolet built its Standard Plans around a specific promise: unused data does not vanish. When a Standard Plan expires, whatever gigabytes remain convert automatically into Koins, Kolet's in-wallet currency. The rate is fixed: 1 EUR equals 100 Koins.

This matters in concrete terms. You buy a 10 GB Standard Plan for a ten-day trip to Thailand. You use 6 GB. At plan expiry, the remaining 4 GB converts to Koins proportional to their value. Those Koins sit in your wallet and apply directly to your next Kolet plan, whether that is a Standard Plan for your next destination or an Unlimited Plan billed by the day.

No expiry date on the Koins. No minimum threshold to unlock them. No form to fill out.

It is also worth knowing that Kolet's Standard Plans carry 30-day validity from your first connection, not from your purchase date. You are not burning through your window while you are still in the air.

The startup was founded in Paris in January 2024 by three entrepreneurs who were, by their own framing, frustrated with exactly this kind of quiet value extraction by legacy operators. The Koins system is a direct structural response to the overselling problem. Kolet has since served over 500,000 travellers across 190+ countries, and became the only major travel eSIM provider to earn B Corp certification, in January 2026, with a score of 99.7 out of 200.

Beyond Koins, Standard Plans earn Flying Blue Miles on all Kolet data plans, at 10 Miles per euro spent, provided you have linked your Flying Blue account in the app before making the purchase. Miles are not credited retroactively, so link first, then buy.

If you travel once a year and always consume your full data allowance, the absence of a travel eSIM unused data refund policy at Airalo or Nomad may never sting. Their plans are widely available, competitively priced, and functionally fine for light use.

If you travel frequently, carry varying data needs trip to trip, or tend to overbuy out of caution, the Kolet model changes the calculus. Buying a larger Standard Plan becomes lower risk. The per-GB cost drops, and any leftover data converts to value you carry forward rather than value you forfeit.

The comparison is not about which provider has slightly better speeds or coverage on a given route. It is about which model is structurally honest about what happens when you do not use everything you paid for. On that specific question, only one provider has a real answer.