eSIM vs Local SIM Card: Which Is Actually Cheaper?
Every eSIM comparison site will tell you an eSIM is more convenient than a local SIM card. Fewer of them will tell you it usually costs more. Travellers say this constantly in places like r/eSIMs and r/backpacking, and the real prices back it up. That doesn't make eSIM the wrong choice — it makes "convenient" and "cheap" two different questions. Here's both, with real numbers for Vietnam, one of the most-discussed destinations for exactly this comparison.
The price reality
Vietnam, checked August 2026
Local prepaid SIM (Viettel, Vinaphone or Mobifone): roughly $3–15 for a data package covering a typical trip, bought at the airport or a phone shop, plus a small one-off SIM fee. Usually includes a local number, calls and SMS.
Saily eSIM for Vietnam: starts at $3.99 for 1GB over 7 days, scaling to around $28.99 for 20GB over 30 days, or roughly $71.99 for a 30-day unlimited plan. Price per GB drops the more you buy, but at typical two-week data use it still lands above the local SIM.
Where the local SIM wins
- Cheaper per GB at the data levels most trips actually use
- Comes with a real local number for calls, SMS, and any local app that asks for one
- No pre-trip planning — buy it when you land
Where the eSIM still wins
- No airport queue, no handing your passport to a kiosk, no physical card to lose
- Active before you land — buy and install from home, connects automatically
- Your home SIM stays in, so your usual number keeps working for calls and banking codes
The catch nobody mentions
The local number gap
In Vietnam specifically, a local +84 number is what apps like Grab and Zalo expect for registration, and what banks send OTP codes to. A local tourist SIM includes that number automatically. Most data-only eSIMs don't include one at all. If your trip leans on local apps like these, check whether your eSIM plan includes a number before you rely on it — don't assume it does.
So which one actually wins?
Two weeks or less and you don't mind one queue at the airport: the local SIM usually wins on price, and it gives you the number local apps expect. Landing at 2am, want zero admin, or moving across several countries where buying a fresh local SIM at every border is its own hassle: the eSIM's few extra dollars buy real convenience — that's a fair trade, not a markup. The mistake is assuming one is always right. Check the actual numbers for where you're going.
Coverage, speed and the local quirks vary a lot by country — that's exactly what our destination pages cover.
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