"My French journalist friends who had covered the Indo-China war used to talk with a far-away look in their eyes about the beauty of Ha Long. The bay had the ethereal quality of a Chinese silk screen: towering rocks covered with vegetation jutted like dragon's fangs out of fifty miles of emerald water. Coastal junks with their bat wing sails, reddish-brown, glided through the rock-studded bay; the whole composition so peaceful and unusual that it seemed not of this world."
You are not restricted to just being on the ship though. We can easily arrange kayaking excursions in the waters.
And if you see an island you like, go on ahead and paddle in that direction. Once on land, explore the area! We recommend Sung Sot Cave, one of the most imposing grottos in the area. Brought your swimming gear? Good. Strap them on and jump in the waters.