How to use your home SIM card and eSIM in Vietnam without unexpected roaming charges?

If you use an eSIM for data, you can disable your home SIM entirely in the phone settings and turn it back on only when you need to receive an SMS code. This further reduces the risk of accidentally using paid roaming data.

To top up a Vietnamese SIM card balance and be able to send SMS (e.g. for service registration), visit a nearby FPT Shop in Nha Trang.

Wi-Fi calling is a great free option: you can make and receive calls on your home number using your regular plan, without paying for international roaming.

On Android, simply disable mobile data and use Wi-Fi calling — no roaming needed and no extra charges.

If you only need internet, a data-only package is enough. Incoming calls in roaming are free, so you can safely share your home number for contact.

Several major Russian carriers offer free roaming in Vietnam. Hotels in Nha Trang provide free Wi-Fi, so internet costs can be kept minimal.

The correct dual-SIM setup (home SIM + eSIM): disable data roaming on your home SIM, enable data roaming on the eSIM. Incoming SMS to your home number are free.

To receive SMS on your home carrier without using data: turn on the phone, disable mobile data on the home SIM. Incoming SMS are free and arrive without an internet connection.