Three ways to have working data abroad. None is best for everyone.
Travel eSIM
Good: Set up before you leave; working data the second you land; keep your home number active alongside it; easy to compare prices in advance; no shop visit, no passport photocopy.
Bad: Data-only (no local number); per-GB cost is higher than a local SIM in cheap-data countries; needs an unlocked, eSIM-capable phone.
Best for: Most short and mid-length trips; anywhere SIM registration is a hassle (India, Thailand’s tourist queues); people who want it sorted from home.
Local physical SIM (bought at destination)
Good: Cheapest per GB, especially in Asia; often includes a local number and calling credit; big data allowances.
Bad: Costs you time on arrival (airport kiosk markups, or a town-centre shop); registration with ID in many countries; you swap out your home SIM (or use a second tray); quality varies by which kiosk you use.
Best for: Long stays; data-heavy trips; countries where local data is very cheap and kiosks are easy (Thailand, Vietnam, Indonesia, Turkey).
Home-carrier roaming pass
Good: Zero setup; your normal number just works for calls and texts; fine for a short trip.
Bad: Usually the most expensive per day; “unlimited” is often throttled hard; some plans exclude your destination.
Best for: Very short trips (2–3 days); people who must keep their normal number fully working for calls/SMS; anyone who values zero effort over cost.
A common setup that works well
Keep your home SIM active for calls and 2FA, and add a travel eSIM for data. You get your normal number and cheap data at the same time, with nothing to swap. If you’re going somewhere with very cheap local SIMs and staying a while, buy a local SIM on arrival instead of a large eSIM plan.