2026年4月、英国ベトナム洞窟探検隊（British Vietnam Caving Expedition Team）が、ユネスコ世界自然遺産フォンニャ＝ケバン国立公園内で新たな洞窟「チャ・ゲオ（Cha Ngheo）」を発見した。全長583m・深さ45mの陥没型構造を持ち、地下水流と滝が確認されている。同探検隊は今回の調査で新たに26の未知の洞窟を発見し、既知洞窟3件の追加調査と合わせ計29洞窟・総延長13.6kmを調査した。世界最大のソンドン洞を擁するこの地域の地下空間がまだ全容を見せていないことを改めて示した。
The discovery of Cha Ngheo cave and its detailed data
The British Vietnam Caving Expedition Team is a group that regularly conducts cave surveys in and around Phong Nha-Ke Bang National Park. During this expedition, while surveying the Kim Dien Commune area of Quang Tri Province, they confirmed a sinkhole-type opening descending at a steep angle from the surface. Entering inside, they found a large cavity stretching 583m long, 45m deep, and 751m high.
Inside the cave, an underground stream was confirmed, and its flow creates a drop that forms a waterfall. According to the team's report, this cave system "is still developing and may expand into a larger cave network." A formal, detailed announcement is scheduled for late April 2026.
| Item | Cha Ngheo cave | For reference: Son Doong cave |
|---|---|---|
| Total length | 583m | About 9km |
| Depth | 45m | About 150m |
| Height | 751m | About 200m |
| Location | Kim Dien Commune, Quang Tri Province | Quang Tri Province |
| Year discovered | 2026 | 2009 (British team) |
| Characteristics | Underground stream, waterfall, sinkhole-type structure | World's largest cave space |
| Public access | Not open (under survey) | Tour-only access (annual limit) |
The full picture of Phong Nha-Ke Bang National Park
フォンニャ＝ケバン国立公園は、ベトナム中部クアンチ省（旧クアンビン省エリア）に位置する面積約900km²の広大な石灰岩台地だ。2003年にユネスコ世界自然遺産に登録され、推定4億年以上の地質史を持つ。公園内には472の洞窟・鍾乳洞が確認されており、そのうち約40洞窟が観光客に公開されている。
Son Doong (Hang Sơn Đoòng), known as the world's largest cave, is also located within this park, discovered in 2009 by the same British Vietnam Caving Expedition Team. The number of tour participants for Son Doong each year is tightly restricted, with a tour fee set at about 3,000 dollars (roughly 450,000 yen) per person.
今回の探検では、チャ・ゲオを含む26の新洞窟が発見され、さらに既知の3洞窟について追加調査が行われた（合計29洞窟、総延長13.6km）。この成果は、フォンニャ＝ケバンの地下世界が既知のわずか一部に過ぎないことを裏付けている。With foreign tourists visiting Vietnam in the first quarter of 2026 reaching a record 6.76 million,such new discoveries are also drawing attention as tourism resources.
The expedition team members and local reactions
The British Vietnam Caving Expedition Team conducts surveys each year in the dry season in the limestone regions of central Vietnam. It has continued its activities in Phong Nha-Ke Bang since the 1990s, with a record of documenting hundreds of caves, including the discovery of Son Doong.
クアンチ省の観光当局関係者は「新洞窟の発見はフォンニャ＝ケバンの観光価値をさらに高める。チャ・ゲオの地下滝は、既存の観光洞窟にはない独自の特徴だ」とコメントした。
Among local guides, some say, "The sinkhole-type entrance structure makes exploration more difficult, but that's exactly why the untouched nature remains." On social media, cave-exploration enthusiasts in particular reacted with comments such as "Phong Nha hasn't even had 10% of its full extent revealed" and "I hope it gets incorporated into new tour routes."
How Japanese travelers can visit Phong Nha
The nearest access point to Phong Nha-Ke Bang National Park is Dong Hoi Airport. It's about 1 to 1.5 hours by domestic flight from Hanoi or Ho Chi Minh City. From Dong Hoi Airport to the park entrance is about 45 minutes by car.
Currently open cave tours include Phong Nha Cave (boat tour, 150,000 dong = about 900 yen), Paradise Cave (250,000 dong = about 1,500 yen), and Son Doong Cave (about 3,000 dollars = about 450,000 yen, a fully guided 5-day, 4-night tour). Cha Ngheo is not open at this point, but depending on survey results, it could become a tour destination in the future.
With Da Nang's beach tourism season opening on April 25,this period makes a central Vietnam circuit combining Da Nang and Phong Nha an ideal plan to enjoy both nature and the sea.
| Cave name | Tour fee | Time required | Difficulty |
|---|---|---|---|
| Phong Nha Cave | 150,000 dong (about 900 yen) | About 1.5 hours | ★☆☆ Beginner-friendly |
| Paradise Cave | 250,000 dong (about 1,500 yen) | About 2 hours | ★☆☆ Beginner-friendly |
| Dark Cave | 450,000 dong (about 2,700 yen) | About 3 hours | ★★☆ Zipline and mud bath |
| Tu Lan Cave | About 300 dollars (about 45,000 yen) | 1–2 days | ★★★ Intermediate trekking |
| Son Doong Cave | About 3,000 dollars (about 450,000 yen) | Four nights, five days | ★★★★ Advanced only |
The expansion of Vietnam's cave-exploration tourism
Phong Nha-Ke Bang's cave tourism keeps growing year by year. The Son Doong tours operated exclusively by Oxalis Adventure sell out every year, and the 2026 allotment is already close to full. Tours of the intermediate-level Tu Lan and Hang En caves are also gaining popularity.
The Vietnamese government has set a target of 25 million foreign tourists for 2026, and is promoting the development of nature-experience tourism content, including caves.The selection of Vietnam's Lo Lo Chai village as one of the UNWTO's "Best Tourism Villages"also symbolizes the shift toward nature- and culture-experience tourism.
At the same time, balancing tourism development with nature conservation is a challenge. Son Doong limits annual participants to about 1,000, and for newly discovered caves like Cha Ngheo, the process is to prioritize academic surveys first, assess environmental impact, and then decide whether to open them to the public.
Practical information for visiting Phong Nha-Ke Bang
| Item | Details |
|---|---|
| Nearest airport | Dong Hoi Airport (VDH) |
| From Hanoi | Domestic flight about 1 hour / 3,000–8,000 yen one way |
| From Ho Chi Minh City | Domestic flight about 1.5 hours / 5,000–12,000 yen one way |
| Airport → park | About 45 minutes by taxi / about 300,000 dong (1,800 yen) |
| Best season | February to August (dry season) |
| Tour booking | Oxalis Adventure (oxalisadventure.com) is the main operator |
| Where to stay | Phong Nha village (many guesthouses and hostels) |
| Recommended length of stay | 2–3 nights (beginner cave + Dark Cave + nearby sightseeing) |
Summary: watch for the official announcement in late April
The British Vietnam Caving Expedition Team's discovery of Cha Ngheo cave is an important achievement showing that Phong Nha-Ke Bang's underground world is still expanding. Its distinctive form — a sinkhole-type structure with an underground waterfall — holds the potential to be developed into a unique tourism experience in the future.
The official announcement in late April is expected to release the cave's geological data and ecosystem survey results. If you're considering a trip to Phong Nha-Ke Bang, the first step is to experience the currently open Phong Nha Cave or Paradise Cave and get a feel for the scale of the region's underground world.With Da Lat Airport closed until August,if you're touring central Vietnam, the Dong Hoi → Da Nang → Hue route is the most efficient for now.
