Which SIM card to buy in Nha Trang and how much does it cost?

There's an alternative option — the Trip service, a 30-day plan with 5GB of data per day. Cost around 684 RUB. These plans aren't usually shown by default, so you need to look for them specifically.

Viettel is the top pick. Costs around 200,000 VND. Tell the seller you're staying for a month and ask for a data-only plan — they'll show you the right option.

Viettel is reliable. Staff may initially push pricier plans — say you're here for three weeks and they'll bring out a different sheet with better options. Price is around 200,000 VND.

If you have issues with your SIM, go directly to a Viettel branch — they can sort out the plan. From the many options available, ask for a monthly data-only plan.