Best eSIM for Vietnam

If your route includes the Ha Giang Loop or trekking around Sapa, Viettel is the only network that delivers reasonably consistent coverage on mountain roads. Vinaphone and Mobifone drop off much faster outside towns; Vietnamobile and Gmobile have very limited rural infrastructure and are not recommended for the Loop. Even Viettel has dead zones — the road sections between Yen Minh and Dong Van (particularly the more remote valley stretches and higher ridge roads), Ma Pi Leng Pass (largely a dead zone across all networks per first-hand testing March 2025), and deep valleys outside Meo Vac have no signal regardless of provider. The main towns on the Loop (Ha Giang City, Yen Minh, Dong Van, Meo Vac, Du Gia) typically have workable Viettel signal in the evening. Travel eSIM network routing matters: Airalo and Saily typically connect via Viettel or Vinaphone, aloSIM routes via MobiFone, Roamless uses its own multi-network global eSIM that may or may not include Viettel depending on local availability. Verify the underlying network before buying if rural reliability matters.

Zalo is Vietnam's primary messaging app — many drivers, homestays and small tour operators communicate via Zalo rather than WhatsApp. The catch: Zalo registration requires a Vietnamese +84 phone number to receive the OTP. Travel eSIMs (Airalo, Saily, Roamless, aloSIM and Yesim) are data-only and do not provide a Vietnamese number, so you cannot create a Zalo account with them. Workaround: established hotels and tour companies almost always also have WhatsApp or Facebook Messenger — both work fine on travel eSIMs. If you need to communicate with smaller operators who only use Zalo, ask them to message you on WhatsApp instead.