These 8 picks for what to do in Ha Long & Cat Ba are not a blog list. Each one is counted from what real travellers actually wrote; the ones a local checked in person are marked "local-checked". The number on each card is how many travellers mentioned it. Best time to visit: Mar–May & Sep–Nov.
Do
Overnight bay cruise
The usual way people do it — one night sleeping on the boat
916 travellers mentioned local-checkedDo
Cat Ba Island
Base yourself on the island for a few days instead of taking a day tour
709 travellers mentioned local-checkedDo
Lan Ha Bay
The bay next door — same karst scenery, far fewer boats
410 travellers mentioned local-checkedDo
Bai Tu Long Bay
The bay to the northeast, same karsts, far fewer boats
56 travellers mentioned local-checkedDo
Kayaking in the bay
Paddle around the karsts and through the tunnel caves
39 travellers mentioned local-checkedDo
Renting a motorbike on the island
A day looping around Cat Ba
11 travellers mentioned local-checkedDo
Cat Ba National Park
Forest walks on the island, with a climb to a lookout