Many frequent travellers have lived this moment: you land at home, your eSIM plan expires, and a gigabyte or two of data you paid for quietly disappears. Most providers call that a feature. We call it a problem worth solving.

Koins is Kolet's in-app currency, and its core job is to make sure unused data has a second life. The conversion rate is clean and easy to remember: 100 Koins = 1 EUR. When a Standard Plan expires, you can convert any data you didn't use into Koins and they're deposited into your Koins wallet. No claims to file, no support ticket to open.

Standard Plans are the ones eligible for this conversion. They run from 1 GB to 20 GB, cover 190 destinations worldwide and stay valid for 30 days from your first connection. Full speed until the very last megabyte, no throttling, no fair-use cap buried in the footnotes. When those 30 days are up, whatever you haven't used becomes Koins.

You can also earn Koins through referrals and partner gifts, but the unused-data mechanic is the one that makes Kolet structurally different from every competitor on the market.

Think about what this means across a year of regular travel. Say you take eight trips and consistently use 70% of each Standard Plan. Under any other provider, 30% of every plan's value is simply gone. With Kolet, that 30% accumulates in your wallet as Koins, compounding quietly in the background. The more you travel, the more meaningful the balance becomes.

The Koins wallet also integrates with the rest of the Kolet ecosystem. Unlimited Plans, which cover 100+ countries and bill by the day rather than by the gigabyte, can be purchased using Koins. So your leftover data credits from a trip to Tokyo can help fund a daily connectivity plan for your next weekend in Lisbon!

Since March 2026, Kolet has offered international calling directly inside the app. These are internet-based calls, meaning they route over your data connection rather than through a traditional phone network. They are billed per minute and paid entirely in Koins.

The per-minute billing keeps it honest. You pay for exactly the time you use, in a currency you've already earned. If your Koins came from unused data on a previous trip, you're effectively making that call for free, recovering value that would otherwise have expired.

This is the closed-loop logic that sets Kolet apart. Data you don't use in Vietnam becomes calling credit you spend in Colombia. The value never leaves the system; it just changes form.

Koins don't sit in isolation. They connect to a travel loyalty stack that includes Flying Blue Miles, Etihad Miles, and airline partnerships with Air France, KLM, Transavia, Virgin Atlantic, Singapore Airlines, Philippine Airlines, and Vietnam Airlines.

If you link your Flying Blue account in the Kolet app before purchasing any plan, you earn 10 Flying Blue Miles per euro spent on all Kolet data plans. That's in addition to whatever Koins you accumulate from unused data. Two loyalty currencies, one purchase. The Miles must be linked before the transaction, not retroactively, so set that up the first time you open the app.

The result is a system where a single Standard Plan can simultaneously generate Flying Blue Miles on your way out, convert leftover data into Koins on your way back, and fund your next VoIP call before you've even packed for the following trip.

A few practical steps to get the most out of the system.

Choose a Standard Plan sized close to, but not over, what you realistically need. A 3 GB plan on a four-day city break is a reasonable call. If you go over, you can top up mid-trip without reinstalling the eSIM. If you come in under, the leftover converts to Koins at expiry. Either way, you're not penalised...

Install the eSIM at home on Wi-Fi before you travel. Your data doesn't start counting until you use your first megabyte at the destination, so the 30-day clock only begins when you actually need it. Keep your existing SIM in the phone; Kolet runs alongside it, and you keep your regular number for calls and SMS on your home plan.

When your plan expires, open the app and check your Koins balance. If you have a VoIP call to make, it's already funded. If your next trip is coming up, apply the Koins to an Unlimited Plan for a short getaway, or stack them toward a larger Standard Plan for a longer journey.

The system rewards one thing above all: actually paying attention to your data rather than overpaying and forgetting about it.