Roaming charges VN carriers
Vinaphone: ~315k VND/MB (default — expensive). Roaming pack 300k VND/day for 1GB. Viettel: 200k-350k VND/day for 1-5GB. Mobifone: 200k VND/day. All require data pack activation before departure.
2026-03-08 · Roaming
Data roaming in Japan — Cost and alternatives
Vinaphone roaming ~300k VND/MB, Viettel 200k/day. eSIM only 250k VND for 5-day unlimited. 80% savings.
Cost comparison 5-day trip
Vinaphone pack: 300k × 5 = 1.5M VND for 5GB. Viettel 350k × 5 = 1.75M VND for 25GB. OlaChill 5-day unlimited eSIM: $11 = ~270k VND. Savings: 80-85%.
Why roaming is worse beyond price
Speed: roaming often throttled to 2G/3G. Activation: must opt in before departure, often 24h ahead. Scope: only home carrier's partner networks, can miss signal in rural Japan. eSIM uses same local networks as Japanese customers.
When roaming still makes sense
Trip ≤24h and only need <100MB (quick transit). If your phone doesn't support eSIM and you can't get physical SIM in time. Urgent biz trip when you need the SAME phone number for incoming calls.
Best hybrid approach
Keep VN SIM active (for SMS OTP from banks, 2FA). Add eSIM Japan for data. Forward calls to OTT (Zalo/WhatsApp) for voice. Zero roaming charges on VN side if you disable VN data roaming.
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5-min QR install · Free cancel up to 24h · Zalo/LINE support 16/7
