There are trekking routes that don’t need to show off to be memorable. Survival Valley is one of them: you enter on foot, but even after leaving the forest, the sound of flowing water seems to linger in your head.

Where is Survival Valley – Thuy Cung Cave?

Survival Valley lies within the Phong Nha–Kẻ Bàng area, about 15 km south-west of Phong Nha Cave, close to Moọc Spring (around 4 km away). The area includes Cave E (Aquarium Cave / Thuy Cung Cave) and Dark Cave (Diving-Water Cave), with Trẹ Stream flowing nearly 2 km between them.
In English-language references, Aquarium Cave is often referred to as Thuy Cung Cave or E Cave, located within Sinh Tồn (Survival) Valley.

Landscape value

A closed karst basin: once inside, you naturally slow down

Survival Valley feels like a vast green bowl set among limestone mountains. The deeper you go, the steeper the cliffs rise, the denser the forest layers become, and light falls in patches—creating a landscape that instinctively lowers your voice. According to available data, the valley covers roughly 2,000 hectares and forms a closed depression typical of karst terrain.

A seamless “forest – stream – cave” system

This is not a place where you hike the forest, then drive elsewhere to see a cave. Here, the landscape connects in one continuous line: forest → stream → water cave. The journey has a natural rhythm, without the abrupt breaks common in conventional sightseeing tours.

Aquarium Cave: the turquoise water

The most striking highlight is the water cave section, where the water glows a vivid turquoise blue—as if you have stepped into a completely different world from the forest outside. It is a quiet kind of beauty, one that reveals itself more clearly the less you speak.

Trẹ Stream: the “thread of water” linking the caves

Trẹ Stream runs through the entire route, acting both as scenery and as the soul of the trek—cool, clear, and offering moments to pause, breathe, and simply listen to the forest and the water.

Ecological value: a true forest, with depth

Documentation records 142 plant species in the area, along with significant ecological value. Ecotourism here is not about conquest, but about moving the right way—lightly, cleanly, and with respect for the place you are visiting.

What to prepare

Clothing: lightweight, quick-dry fabrics; long sleeves and trousers (for insects and vegetation).
Water activities: swimwear, quick-dry towel.
Footwear: trekking shoes or water shoes with good drainage (avoid waterproof shoes, which trap water and dry slowly).
Small backpack: insect repellent, hat/sunglasses, sunscreen, basic toiletries, dry bag for phone/camera.
Skills: comfort with swimming, SUP, and snorkelling.

Best time to go

If your goal is clear water and a smooth experience, many travel sources recommend April to September as the best period to explore Aquarium Cave (Thuy Cung Cave / E Cave).
(Actual tour operations depend on weather conditions and water levels at the time.)

Tour price

• Adults: 1,450,000 VND per person

• Children 1.1–1.3 m tall: 70% of adult price

• Children from 1.4 m: adult price

• Groups of 4 or more: contact us for the best rate

Included services (summary):
National Park entrance ticket, environmental fees, guide & porter, picnic lunch & drinks, safety equipment (helmet, headlamp, gloves, life jacket), basic shoes (sizes 36–43), dry bags (when required), medical support & rescue services.