Bai Tu Long Bay does not have great connectivity as it is located quite far from main cities. You will have to switch around and change transport, stopping over at a number of intermediate destinations before you reach the bay area. However the effort is all worth it as the spectacular scenery melts away all your complaints.
The closest airport to Bai Tu Long Bay is the Noi Bai International Airport, located 40 km from Hanoi city, from which you can reach the bay area by bus or car. A unique way to splurge is to take a helicopter from Noi Ban to Halong Bay and travel to Bai Tu Long by road.
Cai Rong is a small town centred about a T-intersection and so it doesn't have direct buses from Hanoi. From Hanoi, you may take a bus either to Halong Or Cua Ong. This journey takes about 5-6 hours. From Cua Ong, a Xe Om or a taxi can take you to Cai Rong.
An exciting way of reaching Bai Tu Long Bay from Halong Village is by speedboat. The ride takes about 90 minutes and offers you a breathtaking ride through Bai Tu Long Bay, costing 160,000 VND for Vietnamese and 200,000 VND for foreigners. It drops you off just south of Quan Lan village. You can also take a quick ferry ride (14,000 VND) or rent a private boat (1,600,000 VND) from Cai Rong
Within the bay area, to get to islands, the only means of transport is boats and kayaks. To commute on land, you may choose to rent motorbikes (100,000 VND - 150,000 VND), bicycles (50,000 VND - 70,000 VND) or hail a Xe Om. Hailing Tuk-Tuks can be quite expensive as drivers tend to overcharge. (100,000 - 150,000 VND per vehicle per ride). However, if you wish to get into the gorgeous waters and witness the limestone formations, the best way is to hire a cruise from Ha Long Bay itself or at the Bai Tu Long Bay village (300,000 VND)