Vietnam eSIM Guide: SIM Registration Rules, Ha Giang and Ha Long Bay

For a north-to-south trip through Vietnam, a data eSIM installed before you fly is the easiest option: SimplySIM's Vietnam plans start at £5.89 for 3GB, and you avoid Vietnam's new SIM registration and face-check rules, which apply to Vietnamese SIM cards. Coverage is strong in cities and along the main route, with gaps in the far north around Ha Giang and on remote parts of Ha Long Bay.

Last checked: 15 October 2026. SIM rules and roaming prices change. Check the GOV.UK travel advice for Vietnam and your network's roaming page before you go.

Vietnam's SIM registration and biometric rules

Vietnam has tightened the rules for mobile subscribers over the last two years to fight scams and anonymous SIM cards:

• Decree 163/2024, issued on 24 December 2024 under the new Telecommunications Law, requires networks to check subscriber identity documents against national databases and allows video-call verification of customers.
• Circular 08/2026/TT-BKHCN, from the Ministry of Science and Technology, took effect on 15 April 2026. New mobile subscriptions must pass facial biometric verification at activation, and existing subscribers who move their SIM to a different phone must verify their face again. If they do not, outgoing calls and texts are suspended, and the line can later be cut off completely.

Do the rules affect tourists?

The rules apply to Vietnamese mobile subscriptions. If you buy a local SIM card at the airport or in a shop, you will need to show your passport, and you should expect the seller to register your details and possibly take a photo. The published rules do not set out a separate process for foreign visitors, and the face-check system is built around Vietnam's national identity database, so experiences vary between shops and networks.

A travel eSIM from a provider outside Vietnam, such as SimplySIM, roams onto Vietnamese networks as a foreign subscription. You do not register it with a Vietnamese network or go through the face check. You still need to follow Vietnamese law while you are there.

Mobile networks and coverage in Vietnam

Vietnam has three large networks: Viettel, VinaPhone and MobiFone, plus the smaller Vietnamobile. Viettel has the widest rural coverage, especially in the mountainous north. 4G covers almost all towns and main roads, and 5G is available in the big cities. Older 2G services are being switched off, but any recent smartphone works on 4G.

The north-to-south route

Ha Giang

The Ha Giang loop, through Quan Ba, Yen Minh, Dong Van, the Ma Pi Leng pass and Meo Vac, is one of the most popular routes in Vietnam. Since the provincial merger on 1 July 2025, Ha Giang has been part of Tuyen Quang province, so newer maps may show that name. Nothing has changed on the road. Coverage is good in the towns where most homestays are, but expect stretches without signal on the passes. Download offline maps before you set off, and tell your homestay or easy rider which route you are taking.

Ha Long Bay

Most overnight cruises stay close enough to the islands to pick up 4G for messaging and photos. Some itineraries in Lan Ha Bay and Bai Tu Long Bay go further out, where signal can drop. Many boats have Wi-Fi, but it is often slow. If you need to be reachable, ask your cruise operator about coverage on its route.

What UK networks charge in Vietnam

Vietnam is outside every UK network's Europe roaming zone. These are the prices we found on official pages and price guides:

Most people spend two to three weeks travelling the length of Vietnam. At £8 a day, three weeks costs £168 per phone. Official pages: EE, Three, Vodafone and O2.

SimplySIM plans for Vietnam

Prices are in GBP as shown on 15 October 2026. Unlimited plans include 1GB a day at full speed, then continue at a reduced speed until the next day.

The fixed-data plans can use all three big networks, including Viettel, which helps in the far north. If you use TikTok or ChatGPT, choose a plan marked as supporting them. For a three-week trip, the 10GB plan suits light users, and the 30-day unlimited plan suits anyone who streams or video calls often.

Adding Cambodia, Laos or Thailand? The South East Asia (8 areas) 10GB 30Days plan (£18.51) covers Vietnam, Cambodia, Laos, Thailand, Malaysia, Indonesia, the Philippines and Timor-Leste. See every option on the Vietnam eSIM page.

Setting up before you fly

1. Check your phone supports eSIM and is network-unlocked with our device compatibility checker.
2. Install the eSIM at home on Wi-Fi a day or two before you leave, and keep it switched off until you land in Hanoi or Ho Chi Minh City.
3. On arrival, choose the travel eSIM for mobile data and turn on data roaming for that line.
4. Turn data roaming off on your UK SIM so you do not pay a daily charge. Keep it on for texts if you need bank codes.
5. Download offline maps for Ha Giang, Sapa and any boat trips.

Our guide to dual SIM settings before you fly shows each step on iPhone and Android.

What a travel eSIM does not do

A SimplySIM eSIM is data only and does not include a Vietnamese phone number. Grab, homestays and tour operators work well over WhatsApp or Zalo using data, but if a service insists on a local number for SMS codes, you may need a local SIM, which means registering with your passport.

FAQs

Do Vietnam's new SIM biometric rules apply to tourists?

They apply to Vietnamese SIM cards, including ones tourists buy locally, which must be registered with a passport. A travel eSIM from a foreign provider is not a Vietnamese subscription, so you do not go through the registration or face check.

Is there phone signal on the Ha Giang loop?

There is 4G in the main towns such as Ha Giang city, Dong Van and Meo Vac, but expect gaps on mountain passes and in remote valleys. Download offline maps before you start.

Can I use my phone on a Ha Long Bay cruise?

Usually, yes. Most cruise routes near the islands have 4G, but signal can drop in more remote parts of Lan Ha and Bai Tu Long bays.

How much data do I need for three weeks in Vietnam?

Around 10GB suits travellers who mainly use maps, Grab and messaging. If you stream, upload a lot of video or share a hotspot, choose a 30-day unlimited plan.

Which network is best in northern Vietnam?

Viettel has the widest coverage in the mountainous north. SimplySIM's fixed-data Vietnam plans can use Viettel as well as VinaPhone and MobiFone.