Ha Long Bay eSIM: online among the limestone islands

Ha Long Bay is a boat trip: cruises, kayaks, seaplanes. With the eSIM on from Hanoi, the cruise documents and the day's map are already on your phone.

Boats and seaplanes
UNESCO-listed bay
Misty winters

Illustration: a traveller on the sundeck of a wooden junk between the limestone islands of Ha Long Bay, moored junks behind.

The short answer

An eSIM installed at home gets you online on the way to Ha Long Bay: switch the line on when you land and turn on data roaming for it. Most visitors take a cruise package from Hanoi; independent travellers take a bus to Ha Long City or Hai Phong and a taxi to the port, and a seaplane can be chartered from Noi Bai in about 45 minutes.

Checked October 2, 2026

Where the signal holds

4G and 5G
Vietnam's four networks
Viettel, VinaPhone, MobiFone and Vietnamobile all run 4G mobile services, and Viettel, VinaPhone and MobiFone list 5G as well.
Not measured
On the water
We have not measured signal on the water, between the islands or in the caves. Download your cruise documents, tickets and a map before you board.
Data roaming on
Your eSIM
The eSIM runs on a Vietnamese network and shows that network's name in your phone's settings. Turn data roaming on for the eSIM line.

Practical notes

Getting thereMost visitors take a cruise package that includes the transfer from Hanoi; independently, buses run to Ha Long City or Hai Phong, with a taxi to the port, and a seaplane can be chartered from Noi Bai for the 45-minute ride.
Getting aroundThe bay is seen by boat, from day cruises to overnight junks; 15-minute seaplane rides are bookable over the bay, and taxis get you around Ha Long City. Choose the operator with care: Canadian advice notes boat accidents in the bay and suggests avoiding overloaded or unseaworthy vessels.
PayingThe currency is the Vietnamese dong. You must declare cash over 15 million dong or 5,000 US dollars when you arrive.
When to goSeptember to November brings clear skies and cool air; mist drifts in from December to March; April and May are sunny with a breeze, and June to August is the monsoon season, when cruises can be cancelled.

Before you go (Ha Long Bay)

Install the eSIM at home on Wi-Fi and keep the line switched off until you land. Download offline maps, your cruise documents and your tickets while you still have Wi-Fi, in case the signal dips between the islands. On arrival, switch the eSIM line on, choose it for mobile data and turn on data roaming for that line only.

The plan for this trip

Illustration: a hand holds a phone showing a QR code beside a lotus flower and a small globe.

Least per day

7 days · 15 GB · US$5.88

Tax included. The plan names its Vietnamese network, and whether it has calls or a number, before you pay.

Buy on VietSIM

Questions

Where do Ha Long Bay cruises leave from?

From the international cruise ports at Tuan Chau and Ha Long. The bay's own site lists its visitor routes and licensed boats, and most visitors join a cruise package that includes the transfer from Hanoi.