The Editor says: Guishan Island in Yilan sits off the northeastern coast of Taiwan's main island, roughly ten kilometres from Wushi Harbour. It is an active volcano confirmed by geologists. The main dive sites at Guishan Island are: Turtle Head Milk Sea, Turtle Tail Back Garden, and Guimao Pinnacle. Each site has its own highlights. (When diving at Guishan Island, be sure to bring two Flash Lights, a surface marker buoy (SMB), and a dive knife — fishing nets are abundant.)
Guishan Island Diving – Turtle Head Milk Sea
The main attractions here are the hot-spring sulphur vents and the Sally Lightfoot crab ecosystem. The Turtle Head Milk Sea dive site offers one of the rare experiences in the world of diving inside a natural hot spring. However, the Turtle Head is a headland where two currents collide, creating unpredictable tides and occasional strong surges. Combined with the heavy white plumes billowing from the sulphur vents, visibility is often poor — sometimes so low you can't even read the numbers on your dive computer. It is strongly recommended to dive with a guide and boat operator who are familiar with the local currents and topography. The hot-spring vents are typically located at 20–25 m depth; keep a close eye on your no-decompression time. Recommended certification level: AOW with 80+ logged dives, and ability to deploy an SMB independently.
Guishan Island Diving – Turtle Tail Back Garden
Located to the right of Guishan Island's harbour, this site is sheltered from wind and swell inside the bay. It is a relatively safe entry point for yacht-based freedivers and other water-sports participants. For scuba divers, it is usually scheduled as the final, easy dive of the day. Be aware, however, that this site sits along the harbour edge and the island circumnavigation route, meaning a constant stream of vessels passes through. Scuba divers must deploy an SMB before ascending; freedivers must always use a surface float. Although the maximum depth here is under 10 m, coral coverage is exceptionally high, marine life is thriving, and you may be lucky enough to spot a giant clam (Tridacna spp.) measuring over 80 cm. Recommended certification level: AOW with 20+ logged dives, and ability to deploy an SMB independently.
Guishan Island Diving – Guimao Pinnacle
This dive site is an offshore pinnacle approximately 4 km from Guishan Island. Rising from 60 m depth, it climbs in a sheer 90-degree wall to just 3 m below the surface. The vertical wall facing divers is blanketed in rich coral life, and large pelagic fish occasionally pass by — making this site primarily about witnessing dramatic underwater topography. Guimao Pinnacle sits in a strong-current zone and has no descent line, so timing your dive around slack tide is essential. The area is also an important fishing ground off Yilan, with many fishing vessels on the surface. Large fishing nets frequently drape over the pinnacle's flat top. Recommended certification level: AOW with 80+ logged dives, and ability to deploy an SMB independently.
Special thanks: Offshore Life Studio for supplying the aerial footage used in the opening sequence.
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