The Light and Dark Cave, located on the border between Lan Ha Bay and Ha Long Bay, is renowned for its stunning limestone formations and rich natural environment. It lies within the protected area of the Cat Ba Archipelago Biosphere Reserve, making it an ideal destination for tourists who love kayaking and exploring natural landscapes.

The entire area is divided into two parts: the Dark Cave and the Light Cave. The Dark Cave is quite long and is submerged by the tide at all times, making it impossible to pass through and explore. Meanwhile, the Light Cave is short and illuminated by sunlight. Essentially, the Light Cave has a structure similar to Luon Cave. It is a small archway that can only be accessed by kayak and small boats. Through the archway, tourists will encounter a tranquil round lake surrounded by rock walls of various scales and sizes. Immersing in nature, admiring the rich vegetation, and enjoying the fresh air all create an exciting trip to the Light and Dark Cave.