Green Island · Taiwan · Coral garden · Reef
Nanliao
One coral head, about 31 m around and 18 m down
Area photo: Divervincent · CC BY-SA 3.0
Nanliao Bay on Green Island is dived for a single feature: a massive Porites coral colony standing on the seabed at 18 metres, known locally as the giant mushroom head. Chinese-language records of Lyudao Township describe it as the largest and oldest living coral colony known anywhere; published figures put it at 10 to 12 metres tall and about 31 metres around.
Also known as Nanliao Bay, 南寮灣, Da Xianggu Tou, 大香菇頭.
Where it is and how deep
22.6667° N, 121.4708° EApproximate position — the dashed circle shows where the site lies; your operator's briefing has the mooring.
The dive
The dive is built around one object. The coral head sits on the seabed at 18 metres in Nanliao Bay, and the rest of the dive is approach and circuit: you find the colony, then work your way around a mass of living Porites about 31 metres in circumference and somewhere between 10 and 12 metres tall, depending on which account you read. No published account fixes an entry point or a heading to it, so the route is whatever the shop running the dive uses on the day.
Scale is the reason to come. Chinese-language records of Lyudao Township call this the largest and oldest living coral colony known today, and the comparison drawn there is with Australia's Great Barrier Reef, which holds colonies of greater circumference but none taller than this one. The local names describe the shape better than the measurements do: 大香菇頭, the giant mushroom head, and the steel helmet.
The colony is no longer whole. On 18 September 2016 the dive instructor Yu Minghong found that swell from Typhoons Nepartak and Meranti had broken the living coral away from its base. That break is now part of what you are looking at, so go in expecting a damaged landmark rather than the intact one described in older coverage of the island.
Marine life and season
- Pristine corals
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Fair | Fair | Fair | Good | Prime | Prime | Good | Good | Good | Good | Fair | Fair |
Season follows Green Island: Kuroshio keeps water warm year-round; winter monsoon swell and summer typhoons limit exposed-coast sites.
Know before you go
- The swell that broke the colony from its base in 2016 still reaches this bay — check conditions with a local shop before committing to the site during a storm period.
- The coral is fragile and already damaged: keep fins and gauges clear of the colony and hold trim off it rather than steadying yourself against the structure.
Questions divers ask
How deep is the Nanliao coral head?+
The colony stands on the seabed at 18 metres in Nanliao Bay, which keeps the dive inside open-water depth limits. Published figures put the coral itself at 10 to 12 metres tall, so its crown sits well above the base.
Is the giant coral still there?+
Yes, but damaged. On 18 September 2016 the dive instructor Yu Minghong found that living coral had broken away from the base after Typhoons Nepartak and Meranti. Accounts written before that date describe an intact colony.
Sources
- 綠島鄉 (Lyudao Township) – Chinese Wikipedia — Wikipedia (Chinese)
- Green Island, Taiwan – Wikipedia — Wikipedia
- 南寮, 綠島鄉 – OpenStreetMap Nominatim — OpenStreetMap
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