The Editor says: Green Island and Orchid Island have always been must-visit dive destinations for Taiwanese divers. Rising defiantly from the open ocean far from the mainland, these islands have shaped a marine ecosystem entirely different from the nearshore reef flats of Taiwan proper. Swept year-round by the Kuroshio Current, the waters teem with extraordinary marine life — and the consistently crystal-clear visibility of 50 metres or more has earned them a well-deserved reputation on the world stage. SDI/TDI/ERDI Taiwan instructor 俞明宏 shares a comprehensive breakdown of Green Island's dive sites. Start planning your ultra-high-visibility Green Island dive trip today!
Green Island: Geography & Getting There
Green Island lies in the Pacific Ocean approximately 33 km east of Taitung County. The island has an irregular quadrilateral shape, roughly 4 km from north to south and 3 km from east to west. To get there, you can fly from Taitung Fengian Airport on a 19-seat propeller plane to Green Island Airport, or take a ferry from Taitung Fugang Fishing Harbor to Green Island's Nanliao Fishing Harbor. The island offers a wide variety of guesthouses and bed-and-breakfasts, and casual meals, set menus, and local specialty dishes are all easy to find after a little exploring and comparing.
Green Island is understandably packed with visitors in summer, but as long as you avoid cold-front periods, winter is actually a wonderful time to visit. The island's Amei Mountain and Huoshao Mountain block the powerful northeast winds, so while the northeastern shores can be rough, the southwestern waters offer ideal conditions for water activities. Average sea temperature is around 26°C. Visiting in winter also means escaping the scorching 38°C summer heat and the crowds that rival a night market.
Travel notes:
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Taipei → Taitung by train: approx. 3.5–4 hours (350 km, one-way NT$783)
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Kaohsiung → Taitung by train: approx. 3 hours (165 km, one-way NT$362)
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Taipei Songshan Airport → Taitung Fengian Airport by plane: approx. 45 minutes (one-way NT$ early bird 1,460 – full fare 2,303)
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Taitung Fugang Fishing Harbor → Green Island Nanliao Fishing Harbor by ferry: approx. 50 minutes (one-way NT$260)
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Taitung Fengian Airport → Green Island Airport by plane: approx. 12 minutes (one-way NT$1,070)
Green Island is a tropical island surrounded by the Kuroshio Current, with clear, warm water and a warm, humid climate year-round. The combined forces of tectonic uplift, sea-level changes, and wave erosion have sculpted a coastline of dramatic cliffs and bluffs, reef formations draped like the flounces of a long skirt, and occasional small sandy beaches. The shoreline is densely covered with heat- and drought-tolerant plants such as beach morning glory, sea hibiscus, and screw pine. The coral reef waters nurture an abundance of animals in vivid colors, stripes, and spots. Green Island's sunshine, blue skies, and diverse biological and geographical landscapes draw countless visitors — it is truly the jewel of Taiwan's southeastern seas.
The remarkable marine life beneath Green Island's waves is a natural treasure, especially within the protected areas, where the sheer variety and abundance of species — and the surprisingly close encounters visitors can have with them — never fail to astonish. A recent biological survey of Green Island's shallow coastal waters recorded 168 species of mollusks across 56 families, 75 species of crustaceans across 28 families, 48 species of echinoderms across 24 families, and 665 species of fish across 76 families.
Beyond Diving: Green Island's Mysterious Human History
Green Island's rich marine resources have long supported local communities. Fishermen here use longlines, single-hook lines, shore fishing, gill nets, trawl nets, and spearfishing to catch fish. Green Island once exported coral reef fish for the aquarium trade. During the Japanese colonial era, the Japanese introduced pole-and-line bonito fishing, and the catch was processed into dried bonito (katsuobushi) on the island for export. Beyond fishing, Green Island once had a thriving deer-farming industry; though it has since declined, abandoned deer enclosures can still be found on the island. The island's prison — which held political prisoners and serious criminals — has long cast a mysterious shadow over Green Island and stirred the imagination of many visitors.
Today, tourism has become the island's main economic pillar. Visitors can still find the surviving katsuobushi industry; sika deer are often tied up outside shop fronts to attract customers; traditional fishing continues, and boxes of longline catch can be seen as fishing boats return to port. The injustices suffered by political prisoners are gradually being acknowledged through the efforts of many advocates, and a Human Rights Memorial Park has been established. The former prison cells and facilities have been repurposed for commercial recreational use.
Get to Know All 11 Green Island Dive Sites
1. Green Island Dive Site — Da Xianggu (The Big Mushroom)
This massive Porites coral colony, known colloquially as Da Xianggu ("Big Mushroom"), has stood firm at Green Island since 1099 — a span of some 919 years. Its base sits on a sandy seabed at 18 m depth, where the sand layer averages 20–60 cm thick before giving way to andesite bedrock. The coral stands 10 m tall from base to crown, with its top approximately 8 m below the surface. Dome-shaped Porites corals grow slowly — roughly 1 cm per year upward — so by height alone, Da Xianggu is estimated to be around 1,000 years old.
Near this dive site are three tire reef structures that have attracted a considerable number of reticulated damselfish, unique sea anemone species, and the mesmerizing Pacific blue tang (Paracanthurus hepatus). The coral's limestone skeleton hosts a diverse community of organisms: in addition to soft and hard corals, a significant number of nudibranchs have taken up residence here. This site is a remarkably complete ecosystem — nearly every representative species can be found. As of 2018, a total of 174 confirmed fish species have been recorded here.
For divers with the skill and stamina, two routes lead to this site. The fastest option is to enter the water at the end of the breakwater and head at 270°, a straight-line distance of 165 m. Entering from the shore trail at the Shilang Marine Reserve, head at 315°, a straight-line distance of 214 m. How do we know these distances so precisely? Because someone actually went out and measured them with a tape. Either route will involve some current, so be sure to correct for angular drift. (These shore dive approaches are not suitable for beginners!) The safer alternative is a boat dive — you won't have to kick as far, though you'll miss the highlights along the shore dive route.
Note: Da Xianggu was toppled by the massive swells of Typhoon Meranti in the summer of 2016 and now lies at a 45° angle.
2. Green Island Dive Site — Steel Reef (Gangtie Jiao)
Located in the Guiwan subzone, the Steel Reef has seen its batfish population grow from 12 individuals at the time of redeployment to 48 recorded in March of year 99 (of the ROC calendar) — four years later. This tells us something important: artificial reef deployment must be carefully evaluated and accompanied by thorough communication with local communities, but it is far from impossible. We observed nearly 80% biological coverage on the reef structures. When rare species are discovered, swift designation of the area as a protected zone by the relevant authorities can meaningfully boost the value of both ecotourism and fisheries.
The batfish found at Green Island should properly be called the longfin batfish. It is one of three species in the genus Platax within the family Ephippidae, with the scientific name Platax teira (Forsskål, 1775). In Chinese it is called 尖翅燕魚. Juveniles prefer lagoons and shallow reef flats, where they mimic dead leaves and drift with the waves to evade predators — a behavior commonly observed in juveniles around Zhongliao Harbor and Gongguan Harbor on Green Island. Foreigners often call them batfish.
Male longfin batfish develop a pronounced bump on the forehead, and their cloaca is pointed and narrow; females have a rounder, more blunt head and a broader, rounder cloaca. Both sexes show no distinction in their attitude toward humans — they are equally fond of approaching people.
Both at Green Island and abroad, observers have noted a curious phenomenon: when an artificial rope is placed near a batfish habitat, the fish gather in a group around the rope, stop dispersing from their home area, and form a column-like formation along the rope. This behavior has been consistently observed but is not yet fully understood. A reasonable hypothesis is that the rope creates a conspicuous vertical landmark, making the habitat more visible and effectively expanding the fish's foraging range.
Since a guide rope was attached to the Steel Reef, it has been transformed from a hazardous site into an intermediate-level dive. The prevailing current here runs from northwest to southeast; a solid dive plan is essential before diving this site. In addition to longfin batfish, the marine life includes yellowbanded goatfish, angelfish, wrasse, and emperor fish, among other coral reef species. The dominant corals are soft corals, acropora, and small gorgonians.
3. Green Island Dive Site — Six-Metre Reef (Liumi Jiao)
Six-Metre Reef is a small underwater hill rising from the seabed, located approximately 170 m straight offshore. Its top plateau sits just 6 m below the surface and is blanketed with anthias and various wrasse species. Nearby is an open cave whose tiny inhabitants could keep you busy for two full scuba tanks — though they require a careful, patient eye.
The ridge that rises near the surface runs approximately 50–60 m horizontally, and the vertical reef face is well worth exploring — though be aware that the longshore current at Six-Metre Reef can be very strong, making a boat dive the preferred option. Extending further offshore, at 33 m depth, lies an expansive forest of whip corals, curling black corals, and sea pens, where roughly 200+ schooling Moorish idols drift in spectacular formation. Three sea turtles have established regular resting spots here, but given the strong current and depth, a thorough dive briefing from a dive guide is absolutely essential.
4. Green Island Dive Site — Shilang Marine Reserve
The Shilang Marine Reserve is currently the finest model marine protected area (MPA) in all of Taiwan — a high-quality dive site born from the sustained efforts of researchers and divers committed to its protection. The site is less than a one-minute drive from the ferry pier, and within the reserve, surgeonfish, parrotfish, wrasse, butterflyfish, damselfish, and grouper have reached such population densities that the reef seems to pulse with life. During high tide, fish of all species congregate in water as shallow as 1 m to feed (grazing algae off the rocks) — a truly spectacular sight.
In the outer zone surrounding Shilang are four additional landmark dive sites: Zhong Xianggu (Medium Mushroom, standing 4.5 m tall), Dragon Head Rock, Back Garden, and Turtle Rock. All of these sites, like Shilang itself, share a characteristic abundance of soft coral, which harbors all manner of unusual creatures well worth seeking out together.
Note: Xiao Xianggu (Small Mushroom) was knocked over by a typhoon in 2016 and the coral is still in the process of recovering.
5. Green Island Dive Site — Electric Pole Reef (Diangan Jiao)
In 2004, the Fisheries Agency of the Council of Agriculture deployed 150 decommissioned utility poles as artificial reefs along the outer boundary of the Shilang Marine Reserve. So why visit this site? Because it's worth seeing firsthand just how poorly conceived that policy decision was. The idea of conducting coral restoration in Green Island — already celebrated as a coral paradise — was jarring to begin with. Today, these artificial reefs lie scattered haphazardly across the sandy seabed. According to international literature, concrete reefs have limited effectiveness in attracting fish and support only slow coral growth; denser materials such as wood or steel structures are demonstrably more effective for fish aggregation.
What makes this particularly controversial is that these utility poles were deployed directly on top of the only habitat in all of Green Island where Heteroconger hassi — the garden eel — lives. The large-scale destruction of their habitat reduced a colony of approximately 800 individuals to around 400 recorded today.
The sea cucumbers found here — milk fish sea cucumber, white teatfish, and two species of pineapple sea cucumber — are the site's signature indicator species. Large schools of barracuda are also a reliable highlight and practically guaranteed on any visit.
6. Green Island Dive Site — Guiwan Bi
Guiwan Bi is a dive site where two longshore currents converge: one flowing from north to south from Shilang, and another flowing from east to west from Wugui Cave; they merge at Guiwan and flow together toward bearing 330°, joining the main Kuroshio Current. Water depth ranges from approximately 15 to 30 m. The defining feature of this site is an extensive aggregation of Acropora palifera (white branching coral), complemented by a wide variety of other abundant corals. Sea turtles and members of the family Scombridae are frequently encountered here.
7. Green Island Dive Site — Jizai Jiao (Chicken Reef)
Jizai Jiao is formed by an enormous coral reef platform whose base sits at 31 m depth. From the steep "chicken head" cliff face at 18 m, the wall drops sharply to the seafloor more than 30 m below. The dramatic topography and powerful currents draw large pelagic species here to feed; the characteristic fish of this site include yellowback fusiliers, bignose unicornfish, pennant bannerfish, double-lined trevally, and many-spotted butterflyfish.
Coral coverage is dense across the entire reef platform, dominated by acropora, Porites, and gorgonians, with soft corals relatively scarce. The prevailing current here runs primarily from southeast to northwest.
On the southern side of Jizai Jiao lies a massive open-mouthed reef formation — nicknamed "Crocodile Mouth" for its striking resemblance to a gaping crocodile. The Crocodile Mouth bottoms out at 33 m, with the reef structure rising approximately 7 m. Looking further south from the reef, you'll find the densest gorgonian forest in all of Taiwan, blanketing the 30–40 m depth contour.
Diving at this site demands a thorough dive plan and must be conducted under the guidance of a dive guide who knows the terrain well, in order to avoid unnecessary hazards.
8. Green Island Dive Site — Zhongliao Harbor
Zhongliao Harbor sits on the northern side of Green Island, along the road leading to the Green Island Lighthouse. The harbor is about 3 m deep and currently has no vessels moored — it's an idle little port. Its calm, sheltered waters and easy entry have made it a swimming spot for both tourists and locals alike, and it's a popular venue for introductory scuba experiences. In summer, heavy visitor traffic tends to stir up sediment and cloud the water. As a result, most daytime divers — other than training students — will head beyond the harbor and swim north along the channel.
Just outside Zhongliao Harbor, you'll encounter a channel blasted through the coral reef, followed by a vertical drop of about 4 m, beyond which lies a sandy plain dotted with small, isolated reef patches.
Experienced divers tend to save Zhongliao Harbor for night diving. The invertebrate life inside and around the harbor is exceptionally rich, and different species of nudibranch appear with the changing seasons, making it a favorite spot for macro photographers.
9. Green Island Dive Site — Grand Canyon (Da Xiagu)
This site is located approximately 1.2 km offshore from Gongguan Harbor. It shares similarities with the "One Line of Sky" site, but features wider fissures — the largest reaching 8 m across, the smallest 3.5 m — with fissure depths of up to 25 m. The reef base sits at 46 m, with the reef top just 3 m from the surface. The current flows from south to north. Unicornfish of the genus Naso — particularly bignose unicornfish and Vlaming's unicornfish — along with fusiliers, are the most commonly encountered species here.
10. Green Island Dive Site — Three Rocks (Sankuai Shi)
This site is situated on the outermost reef at the far northeastern tip of Green Island. The reef base reaches 65 m depth, while the exposed rock stands 3.5 m above the surface. The current is the main Kuroshio flow running south to north. The characteristic marine life is dominated by surgeonfish and fusiliers, with Scombridae species also making regular pelagic passes through the area.
11. Green Island Dive Site — Bird Egg Rock Blue Cave (Niaoluanyan Landong)
Bird Egg Rock is located on the eastern side of Youzhu Lake. A volcanic rock formation rises from 22 m below the surface straight up to 18 m above it. Viewed from a distance across Youzhu Lake, it resembles an egg nestled in a bird's nest — hence the locals' affectionate nickname, "Bird Egg Rock."
On the eastern side of Bird Egg Rock lies a large underwater trench, forming sheer vertical walls on both sides. At its deepest point is a massive natural underwater arch, beyond which opens a natural underwater cave at 25 m depth. Sea turtles frequently rest here, giant trevally regularly patrol the cave in search of prey, and wrasse and moray eels can also be found within.
At the base of the cave entrance, numerous small cavities shelter several orbicular batfish that have made their home there. Circling around Bird Egg Rock, the underwater scenery that emerges is reminiscent of a miniature Guilin — a breathtaking landscape beneath the sea. The current here generally flows from south to north; outside the cave entrance, the current can run swift and strong, and large colonies of gorgonians thrive in the flow.
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