Can I use a local Vietnamese SIM for data while keeping my home SIM for SMS in a dual-SIM phone?

For MTS subscribers, roaming in Vietnam is available through the Vinaphone network: the home SIM can receive SMS, while voice calls are charged as roaming. Use a separate Vietnamese SIM for mobile data.

With a dual-SIM phone, simply buy a local Vietnamese SIM on arrival and use it for mobile data. Your home SIM will continue to receive SMS for free as long as data roaming is disabled on it. No extra phone settings are needed — everything is managed through your home carrier's app or account.

Before your trip, take these steps on your home SIM: disable mobile data roaming, set apps to update only on Wi-Fi, and turn off voicemail/auto-answer so incoming calls don't trigger roaming charges. After that, you can freely use your Vietnamese SIM for data without surprise bills.

Vietnamese SIM cards with data are sold at Cam Ranh Airport and at numerous phone shops throughout Nha Trang. Popular carriers include Viettel, Vinaphone, and Mobifone. Just insert the SIM and data works immediately — no need to visit a service center for setup.