The Bright and Dark Cave is one of the most captivating destinations on the Lan Hay Bay itinerary. Below is an informative guide curated by Halong & Lan Ha Bay Cruise Tours to help you prepare for your journey. We invite you to read on.
Where is the Bright and Dark Cave located?
The Bright and Dark Cave, also known locally as Hang Ca, consists of two small caverns—the Bright Cave and the Dark Cave—spanning an area of approximately 1.1 square kilometers in the northeastern part of Lan Ha Bay, belonging to the Cat Ba Archipelago. This natural cave system was formed approximately 10,000 years ago through the continuous erosion of limestone mountains by rising sea levels. The Bright and Dark Cave is a prime example of a unique arch-shaped karst cave structure: the cave floor lies beneath the sea level, while the ceiling rises above the water. Due to this distinctive architecture, being sheltered by towering mountain ranges ensures completely calm waters, moderate ocean currents, and because it is situated away from standard cruise and boat routes, visitors can only explore it via kayak or a traditional bamboo boat.
Bright and Dark Cave
While the Dark Cave is relatively deep and narrow, spanning about 200 meters in length, it receives very little natural light and is frequently submerged by the tide, often resting entirely below sea level. Consequently, entering the Dark Cave requires kayaking and carrying a flashlight. In contrast, the Bright Cave is larger, featuring a height of 3 meters (varying with the tide), a width of 4 meters, and a length of 100 meters, making it ideal for tourism activities. During high tides, seawater can rise to touch the cave ceiling. The Bright Cave bears a striking resemblance to Luon Cave in Ha Long Bay; as travelers glide inside, rays of natural light stream through crevices in the rock, creating an ambiance reminiscent of a magnificent cathedral sculpted by Mother Nature herself.
Notably, this is also the only location in Lan Ha Bay where visitors can explore four tunnel caves within a single area: the Dark Cave, the Bright Cave, the Bat Cave, and the Sua Cave. Among them, the Bat Cave stretches over 100 meters, while the Sua Cave is a towering arched cavern accessible by small boat or kayak.
Experiences and How to Visit the Bright and Dark Cave
The Bright and Dark Cave is currently included in routes 2 and 3 of Lan Ha Bay cruise excursions. Therefore, travelers can choose between a day trip or an overnight Lan Ha Bay cruise. Departing by boat from Cai Beo Pier takes approximately 80 minutes to reach the cave. Along the way, guests can admire prominent Lan Ha Bay attractions such as Turtle Islet, Buddha Statue Islet, Cua Van, Ba Trai Dao, and Pen Islet… If departing from Ben Got Pier (Cat Hai Island), the journey is longer and takes about 2 hours to reach the destination.
Due to the natural characteristics of these caves, entering them requires choosing one of two transportation methods: kayaking or riding a traditional bamboo boat:
- Kayaking: Each kayak accommodates a maximum of 2 adults (ages 15 to 65 with no chronic illnesses). Children under 15 or seniors over 65 must share a boat with a physically fit adult within the permitted age range. The designated hours for kayaking here are in the morning from 10:00 AM to 12:00 PM and in the afternoon from 2:00 PM to 4:00 PM.
- Bamboo Boat (Sampan): This is a safe and convenient option for travelers who do not know how to kayak, or for families traveling with young children and elderly members. Local fishermen from the nearby floating village will row visitors through the caves. Each bamboo boat can carry between 4 to 6 passengers.
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For travelers wishing to explore all four caves in this area (the Dark Cave, Bright Cave, Bat Cave, and Sua Cave), the kayaking or bamboo boat route spans approximately 5.3 kilometers, taking about 90 minutes. In the event of high tides or when the bay management board restricts access to the Dark Cave, visitors will tour the remaining 3 caves: the Bright Cave, Bat Cave, and Sua Cave. The route for these three caves is approximately 4.1 kilometers, taking about 45 minutes. The permitted hours for kayaking in this area are in the morning from 10:00 AM to 12:00 PM and in the afternoon from 2:00 PM to 4:00 PM.
The Dark and Bright Cave area lies within the core zone of the Cat Ba Archipelago UNESCO Biosphere Reserve, renowned for its exceptionally high biodiversity both marine and terrestrial. Consequently, during their exploration, travelers frequently spot various primate species foraging or playing along the forest patches within the valley lagoons, such as the Cat Ba langur, rhesus macaque, and stump-tailed macaque…
