eSIM

Best Singapore eSIM for Vietnamese (What I Wish I Knew)

You land at Changi, the Grab driver calls, and your Vietnamese SIM is on a roaming bill you will only see next month. Here is the eSIM setup that keeps Zalo and bank OTP alive without the bill.

Quick answer: For a Vietnamese traveller on a 3 to 5 day Singapore trip, buy a data-only eSIM before you fly and keep your Vietnamese SIM in the phone for Zalo and bank OTP. Singapore has no tourist dead zones: coverage is strong across the city centre, MRT stations and malls, so the only real choice is how much data you buy.

Key takeaways

Keep your Vietnamese SIM active. A data-only travel eSIM has no phone number, so your bank OTP and Zalo messages keep arriving on your Viettel, Vinaphone or Mobifone line while the eSIM carries the data.
Singapore has no coverage problem to solve. Coverage is strong across the city centre, MRT stations and malls, so pick a plan on price and data size rather than on network.
Size for the whole trip, not per day. Travel eSIM plans cannot be topped up, so a 5 GB plan for a 4 day city break leaves headroom for Grab, maps and photo uploads.
The local tourist SIM is the honest alternative. Singtel's hi! Tourist range and StarHub tourist plans need passport registration at a counter, so they suit travellers who want counter help or a local number (thesingaporebest.com, 2026).

Picture the arrival at Changi late at night: the Grab driver calls, your Vietnamese SIM has no data line, and the roaming bill only shows up after the trip. That is the scenario this guide is built to avoid, and the fix starts before you leave home.

Which network should Vietnamese travellers use for a Singapore eSIM, and what is the real speed?

For tourists, the difference between carriers is almost negligible for tasks like maps, Grab calls or messaging.

The only weak spots are the interiors of older thick-walled buildings. If you are in the city centre, an MRT station or a shopping mall, the signal is almost always stable for maps, Grab calls and messaging.

How many GB do you need for 4 days in Singapore?

Travel eSIM plans cannot be topped up, so size for the whole trip, not per day.

There is no single measured figure, so treat any daily number as a rough guide only. For a normal city break, maps, Grab, messaging and photo uploads sit in the low hundreds of MB a day, and a 5 GB plan over 4 days covers that with headroom.

Where to buy a Singapore eSIM?

Fizen sells Singapore eSIM plans you can buy before you fly. Pick your data size and number of days, and the shop page shows the current price.

Prices and plan details change; check the current terms before you buy.

Do Zalo and Vietnamese bank OTP work in Singapore?

Most travel eSIMs are data-only and come with no phone number, so you cannot receive bank OTP by SMS on the eSIM alone. Zalo still works because it uses internet data.

To receive bank OTP, keep your Vietnamese SIM in the phone and leave it on for calls and SMS. Check roaming SMS fees with your Vietnamese carrier before you fly.

How do Singtel, StarHub and M1 tourist SIMs bought at Changi differ?

Carrier	Plan	Validity	What to know
Singtel	hi! Tourist, several data tiers	7 days and 30 days	For foreign passport holders only; some call and SMS features need verification at a hi! store (thesingaporebest.com, 2026)
StarHub	Tourist Plans and Traveler eSIM	Varies by plan	Available at arrival halls T1, T2, T3, T4; eSIM needs identity verification and activation within a set window (starhub.com, 2026)
M1	30-day data-only plan	30 days including the registration day	Available as physical SIM and eSIM; data-only plans have no calls and SMS (thesingaporebest.com, 2026)

Prices change over time and by data size, so this article does not list specific plan prices. Travel eSIM plans are available from about US$0.30 a day. Check the current price on the shop page before you buy.

Frequently asked questions

Can I keep my Vietnamese SIM active while using an eSIM in Singapore?

Yes. Set the eSIM as your mobile data line and leave your Vietnamese SIM on for calls and SMS. Turn off data roaming on the Vietnamese line so you do not pay roaming rates, and keep it on for bank OTP and Zalo.

Does a travel eSIM give me a Singapore phone number?

Most travel eSIMs are data-only and come with no phone number, so you cannot make local calls or send SMS. If you need to call a hotel or restaurant, buy a Singapore tourist SIM with a local number instead.

How much data do I need for 4 days in Singapore?

Is Singapore mobile coverage good enough for Grab and maps everywhere?

Yes. Coverage is strong across the city centre, MRT stations and malls. The only weak spots are the interiors of older thick-walled buildings (DriftAsia, 2026).

When does a Singapore tourist SIM beat an eSIM?

When you need a local number for calls or SMS, when your phone does not support eSIM, or when you want counter help. Singtel's hi! Tourist range needs passport registration at a counter, so it suits travellers who want that in-person setup.

Get your Singapore eSIM before you fly

Card, Apple Pay or Google Pay on the web store. Pick your data size and number of days, and the shop page shows the current price.

Choose your Singapore plan

Terms and conditions

Information only. This article is information only. It is not an offer or sale, and it is not advice. Prices and plan details change; check the current terms before you buy.
For readers in the United States. This is information only, not an offer or sale, and not advice. Fizen is not offered to US Persons.
Data-only plans. Travel eSIM plans described here are data-only unless stated otherwise. They do not include a phone number and do not support voice calls or SMS.
Coverage and speed. Carrier and network facts come from the sources listed below and from the dated sources listed. Actual speed and coverage depend on your device, location and network load.

Sources

All carrier, price and coverage facts in this post were checked on 14 October 2026.