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The Editor says: Guishan Island in Yilan is located off the northeast coast of Taiwan's main island, approximately ten kilometers from Wushi Harbor. It is an active volcano confirmed by geologists. The typical Guishan Island dive itinerary covers three dive sites: the Milk Sea at Turtle Head (龜首), the Back Garden at Turtle Tail (龜尾), and the Pinnacle Reef at Turtle Mao (龜卯). Each site has its own unique highlights. (When diving at Guishan Island, be sure to bring two torches, a surface marker buoy (SMB), and a dive knife — there are many fishing nets in the area.)
Guishan Island Diving - Turtle Head Milk Sea (龜首牛奶海):
The main attractions here are the hydrothermal sulfur vents and the gorilla crab (Percnon planissimum) ecosystem. The Turtle Head Milk Sea dive site offers one of the rare experiences in the world of diving directly within a hot spring. However, the Turtle Head is a headland formation where two currents collide, creating highly variable tidal conditions and occasional strong currents. The large plumes of white sulfurous smoke from the vents also mean visibility is often poor — sometimes so low that you cannot even read the numbers on your dive computer. It is strongly recommended to hire a dive guide and boat operator familiar with the local hydrology and topography. The hot spring vents are typically located at depths of 20–25 m; keep a close eye on your dive computer's no-decompression limit. Recommended certification level: Advanced Open Water Diver (PADI cert) with 80+ logged dives, and ability to deploy a surface marker buoy (SMB) independently.
Guishan Island Diving - Turtle Tail Back Garden (龜尾後花園):
Located to the right of Guishan Island's harbor, this site is sheltered from wind and swell by the bay. It is a relatively safe entry point for yacht-based freedivers and other water sports enthusiasts. For scuba diving, this spot is typically arranged as the final, relaxed dive of the day. However, as it sits along the harbor edge and the island-circling boat route, there is a constant flow of vessel traffic. Scuba divers must deploy a surface marker buoy (SMB) when ascending, and freedivers must use a surface marker float at all times. Although the depth here does not exceed 10 m, coral coverage is remarkably high, marine life is abundant, and lucky divers may even spot giant clams (Tridacna spp.) exceeding 80 cm in size. Recommended certification level: Advanced Open Water Diver (PADI cert) with 20+ logged dives, and ability to deploy a surface marker buoy (SMB) independently.
Guishan Island Diving - Turtle Mao Pinnacle Reef (龜卯獨立礁):
This dive site is an underwater pinnacle reef located approximately 4 km by boat from Guishan Island. Rising from a depth of 60 m, its sheer 90-degree walls shoot upward to just 3 m below the surface. The vertical walls are richly covered in coral, and large pelagic fish are occasionally spotted passing by — making this site primarily a destination for photographing dramatic underwater topography. The Turtle Mao Pinnacle Reef sits in a strong-current zone, and with no descent line available, timing your dive for slack tide is essential. This area is also an important fishing ground for Yilan, with many fishing vessels on the surface. The reef platform is frequently covered in large fishing nets. Recommended certification level: Advanced Open Water Diver (PADI cert) with 80+ logged dives, and ability to deploy a surface marker buoy (SMB) independently.
Special thanks to: Offshore Life Studio (離岸生活工作室) for providing the aerial footage for the opening sequence.
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Frequently Asked Questions
How is a BlueTrend dive trip different from an unknown, no-name dive group?
Choosing us means full peace-of-mind protection and a smooth experience from start to finish. Every trip we run holds to three things.
First, full legal protection and a professional dive leader: we strictly follow Taiwan's travel regulations and provide complete travel-agency liability insurance, travel insurance, trip-inconvenience insurance and dive insurance. Every group is accompanied by a certified, foreign-language dive leader who joins you on both the dives and the land itinerary, liaising seamlessly with local dive shops and operators on your behalf to keep things running smoothly — the person our travellers trust most.
Second, fully licensed with secure payments: every payment goes into a licensed travel agency's account, with multiple safe payment channels (bank transfer, credit card and more) and a legal collect-and-remit receipt, so every transaction is open, transparent and protected, avoiding the fraud and dispute risks of transferring money privately to an individual.
Third, hand-picked quality we vet in person: every trip, dive site and partner shop is scouted on the ground by our own team, from the guides' professionalism and safety standards to the food, lodging, environment and service details on land, all vetted by us so you don't get caught out.
I want to sign up for a dive trip. Are there certification-level or logged-dive requirements?
Each dive site is different, so the entry bar varies. 'Bali Tulamben', for instance, is relatively beginner-friendly. 'Malapascua in the Philippines' is also beginner-friendly, but since thresher sharks tend to cruise between 20 and 30 metres, we recommend AOW certification with 20+ logged dives to enjoy this trip comfortably. For 'the Maldives' or 'Palau', we suggest AOW with 50+ logged dives for a more relaxed experience. If you're not sure whether your experience fits the trip you want, message us and our dive editors will assess it and help you find the trip you'll feel safest on.
Can I join if I'm signing up alone? How are rooms arranged?
Plenty of our travellers sign up solo! For rooms and beds, we prioritise pairing you with a same-gender traveller, and if you'd rather have your own space you can pay the difference to upgrade to a single room. For the diving, our professional leader will pair you with a suitable buddy, and with the happy vibe on our trips you'll quickly make a great group of dive friends. Many people sign up alone, make new friends, and end up organising the next trip together!
Does the trip fee include dive insurance, gear rental, taxes and instructor tips?
It depends on the trip, the destination's regulations and the local operators. Every BlueTrend dive trip has a detailed web page with a clear 'included / not included' list, transparent and with no hidden charges. All payments are collected by a licensed travel agency, with a standard-form contract for your protection.
I'm a new diver / haven't dived in a long time — will I fall behind the group?
Before you complete your booking, our team assesses a suitable trip based on your certification level and experience. Before departure, we strongly recommend taking time to refresh in Taiwan with an instructor, or a fun dive to get your feel back. On the trip itself, our professional dive leader groups and pairs everyone by experience, keeps a close eye underwater on travellers who need extra care, and steps in to help right away.
Will the photos and videos taken during the trip be shared with us?
During the dives, 'safety' is always the leader's top priority, so whenever it's suitable and safe the leader will capture great shots and record the best moments. During or after the trip, we compile a cloud album for all travellers to download, so you go home loaded with memories!
Besides your scheduled trips, can you arrange a private group charter or independent travel for me and my friends?
Absolutely! Besides group trips, we also arrange private group charters and independent travel. We can communicate, enquire and coordinate services with local operators based on your needs, saving you time and effort and taking the language barrier off your plate, to tailor the smoothest, most reassuring dive trip just for you. Contact our LINE support and our editors will arrange it for you!
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