Paying $12 per day for international roaming because you forgot to sort out a local SIM before leaving the airport — we've all been there. And the eSIM landscape has changed so fast in the last two years that advice from 2023 is already outdated. Here's what actually works in 2025 for staying connected without overpaying or losing your home number.
The Dual-SIM Setup That Covers Everything
If your phone supports eSIM (iPhone XS and newer, most Samsung Galaxy S21+, Google Pixel 3a and up), keep your home SIM as the physical card for receiving bank verification texts and keep an eSIM slot for local data. Airalo offers regional eSIM plans — their Asia-Pacific package gives you 5GB across 15 countries for $16, which beats buying individual SIMs if you're country-hopping every two weeks. For longer stays, local SIMs still win on value. Thailand's AIS gives you 30GB for 30 days at 599 baht ($17) from any 7-Eleven. Vietnam's Viettel offers 90GB for 30 days at 200,000 dong ($8) — buy it at the airport counter, not from touts outside. Indonesia's Telkomsel provides the widest coverage across islands, critical if you're heading beyond Bali to Flores or Sumba. Always buy SIMs at official carrier shops or airport counters where they'll register and activate it properly — unregistered SIMs in Indonesia get deactivated within 24 hours.
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Download Roammate — FreeKeeping Your Home Number Alive Without Paying Full Price
The nightmare scenario is your bank's two-factor authentication texting your home number while it's sitting in a drawer back in London, unreachable. Before you leave, call your carrier and ask about their cheapest plan that keeps your number active and allows incoming SMS — in the UK, Three offers a pay-as-you-go plan for as little as a single top-up every 6 months. In the US, T-Mobile's cheapest prepaid plan at $10 per month keeps your number alive and forwards texts. Set up a Google Voice number as a permanent backup before departure, since it gives you a US number that works over wifi anywhere in the world. For banking specifically, switch to app-based authentication (like Authy or your bank's own app) before departure rather than relying on SMS codes. HSBC, Wise, and Revolut all support app-based verification that works regardless of which SIM is in your phone.
