This is the one route on Cat Ba that only we know. Starting with an easy warm-up ride around Khe Sâu village, the journey turns inland — trekking through a mountain gorge that most visitors never even know exists — before emerging at a hidden pocket of Lan Ha Bay. Here, a local fisherman's family shows you how their nets are set and worked, a tradition passed down on this coast for generations. From their doorstep, you paddle out by kayak into the bay itself — jungle behind you, open water ahead. Unlike our Viet Hai crossing, this route stays almost entirely off the map: no crowds, no repeated ground, just one continuous line from mountain to sea.