We did the 2-night cruise, which included a bike ride (or electric cart transport if you prefer) to a village and kayaking and/or swimming from a day boat (while 1-night cruisers were swapped for a new group of 1-night cruisers - very efficient operation!). Overall, the cruise was lovely, the scenery magnificent, the food was good, the staff/service was excellent, and the bike ride was great (nice chance to stretch your legs while seeing some beautiful rural settings on Cat Ba) and the kayaking fun (again, a little chance to exercise, and fun to go through some arches under the limestone islands/structures). We were very sad to see the pollution and garbage in the water near Cat Ba - like big chunks of styrofoam and other visible garbage - which made us stay in the kayaks and forego the swimming. Not sure about the origin of this pollution …perhaps an eco-tourism cruise could be offered to help with clean up to preserve this incredible natural beauty?