This question deserves a straight answer, even where the answer does not favour the people selling eSIMs.
Airport SIM counters are usually expensive
A SIM counter at an airport sells to people who have just got off a plane, are tired, do not know local prices and have no alternative in front of them. Prices there are typically 30% to 100% higher than in town.
A local SIM in town can be cheaper than an eSIM
This is true. In Thailand, Vietnam, Indonesia and India, a physical SIM from a convenience store or operator shop can cost noticeably less than an eSIM — sometimes half.
If you are staying a while, speak the language, or have a local with you, buying locally is the sensible choice on price.
But count these too
Time. Finding a shop, queuing, filling in forms. Many countries require a passport and registration. An hour out of a seven-day trip is not free.
The gap with no data. Between landing and buying a SIM you have nothing. That is precisely when you want it: calling a ride, finding the hotel, telling someone you arrived.
The risk of handling your own SIM. Taking out your main SIM to fit another is when it gets lost. Losing your main SIM abroad is far more trouble than the money saved.
Losing your number while it is out. With your home SIM removed you do not receive bank messages, verification codes or calls from home. On a single-slot phone, that is a real trade-off.
When to buy locally
- Staying more than two weeks in one country.
- You need a local number to register for services.
- You use a lot of data and the price gap is large.
- You have a local friend who can help.
When an eSIM makes more sense
- Short trips, under two weeks.
- Several countries in one trip.
- You want data the moment you land.
- You do not want to remove your own SIM.
- Your phone has one slot but supports eSIM.
The straight conclusion
If you optimise for money and have time, a local SIM wins in many countries. If you optimise for having data immediately and no disruption, an eSIM wins. There is no answer that is right for everyone — only one that is right for your trip.