The Coral Triangle
The Gili Islands sit within the Coral Triangle, a region of the Indo-Pacific bounded by the waters of Indonesia, Malaysia, Papua New Guinea, the Philippines, Solomon Islands, and Timor-Leste. This area is the global centre of marine biodiversity, home to 76% of the world's coral species and over 3,000 species of reef fish. Diving or snorkelling in the Gilis means swimming in the most biologically rich ocean on earth.
Sea turtles
Sea turtles are the undisputed stars of the Gili Islands underwater scene. Two species are commonly seen:
Green sea turtle (Chelonia mydas)
The most common turtle in the Gilis, green sea turtles can grow over a metre in length and live for decades. They are herbivores, feeding on seagrass and algae, which is why you often see them grazing on the sea floor around the islands. Despite their name, their shells are actually brown or olive — the "green" refers to the colour of their body fat.
Hawksbill sea turtle (Eretmochelys imbricata)
Smaller than greens and with a distinctive hooked beak, hawksbills are critically endangered globally but still regularly seen in the Gili Islands. They feed on sponges growing on the reef. Their beautiful shells have historically been targeted by poachers, contributing to their decline.
Where to find turtles: Turtle Point (off the north coast of Trawangan), Turtle Heaven (off Meno), and the east coast of Gili Air near the main snorkel area. Turtles are also seen on virtually every dive around the islands. Early morning snorkels typically yield the most sightings.
Turtle etiquette: Do not touch, chase, or harass turtles. Keep a respectful distance. Do not block them from swimming to the surface for air. Do not feed them. Photographs and videos are fine if taken without disturbing the animal.
Reef sharks
The reefs around the Gilis are home to several species of reef shark. They are not dangerous to humans — reef sharks are generally shy and will actively avoid swimmers and divers. A shark encounter is one of the highlights of diving in the Gilis.
Whitetip reef shark (Triaenodon obesus)
The most commonly seen shark species in the Gilis. They can grow up to 1.6 metres long and are identified by the distinctive white tips on their dorsal and tail fins. Whitetips often rest on the sea floor during the day and hunt at night.
Blacktip reef shark (Carcharhinus melanopterus)
Less commonly seen but occasionally spotted in shallower water. Similar in size to whitetips but with black-tipped fins.
Where to find sharks: Shark Point on the north of Trawangan is the most famous dive site for guaranteed sightings. Deep Halik off Meno also has regular sharks. Sharks are almost always seen on full-day dive trips but rarely encountered by shallow snorkellers.
Tropical fish
The Gili reefs are home to hundreds of species of tropical fish. Some of the most commonly seen include:
- Parrotfish — large, colourful fish that crunch coral with their beak-like teeth
- Butterflyfish — small, bright fish in many colour patterns
- Angelfish — elegant, flat-bodied fish with striking patterns
- Sweetlips — chunky fish with thick lips, often in groups
- Moorish idols — black, white, and yellow striped fish with a trailing dorsal fin
- Clownfish (Nemo) — living in sea anemones on the reef
- Trevally — silver schooling predators
- Surgeonfish — oval-bodied fish with a sharp spine near the tail
- Moray eels — hiding in crevices, peeking out with their toothy smile
- Pufferfish — cute, round fish that inflate when threatened
- Triggerfish — sometimes territorial during breeding season
- Lionfish — beautiful but venomous, with long spines
Other marine life
Octopus
Octopuses are common on the reefs but hard to spot because of their incredible camouflage. Look for small holes in the coral or sandy patches and occasionally you will see eyes watching back. Night dives are the best time to see octopus hunting.
Cuttlefish
Cuttlefish can change colour and texture in seconds, making them fascinating to watch. They hover over the reef and seem to study divers curiously.
Nudibranchs
These small sea slugs are among the most colourful animals in the ocean. There are hundreds of species in the Gilis, ranging from fingernail-sized to the length of a pen. Macro photographers adore them.
Stingrays
Blue-spotted stingrays are commonly seen resting on the sandy sea floor around the islands. Stingrays are docile but will sting if stepped on or cornered. Give them space.
Mantis shrimp
Tiny, extraordinarily colourful, and armed with the fastest punch in the animal kingdom. Spotting one is a treat.
Frogfish
Masters of disguise, frogfish look like lumps of coral or sponge. They are prized sights for underwater photographers.
Seasonal visitors
Manta rays
Giant manta rays occasionally pass through the waters around the Gilis, particularly between December and April. These graceful filter feeders can have wingspans of 5 metres or more. Seeing one is a diver's dream.
Whale sharks
The world's largest fish, whale sharks, occasionally visit the region. Sightings are rare but possible, especially during the months of March-April and September-October when plankton is abundant.
Coral reefs
The reefs around the Gilis consist of both hard and soft corals. Hard corals build the reef structure and take hundreds of years to grow. They come in many shapes: branching, plate, brain, massive, and encrusting forms. Soft corals sway in the current and add colour to the reef.
Unfortunately, the Gili reefs have suffered significant damage over the years from coral bleaching (due to warming ocean temperatures), destructive fishing practices in the past, anchor damage, and tourist impact. Conservation organisations are working to restore the reefs through coral transplantation projects that divers can volunteer for. The reefs are still beautiful and full of life but responsible behaviour is essential to their survival.
Land wildlife
The land wildlife on the Gili Islands is modest compared to the marine life, but you will encounter:
Chickens and roosters
Free-range chickens wander everywhere. Roosters will wake you at dawn, which is either charming or annoying depending on your mood.
Cats
Street cats are common on all three islands. Many are friendly but semi-feral. Do not feed them if you don't plan to continue doing so regularly, and do not encourage them into restaurants.
Horses
The cidomo horses are the main working animals on the islands. See the Getting Around guide for notes on cidomo welfare.
Lizards and geckos
Small lizards and geckos are everywhere. Tokay geckos make a distinctive "tok-ay" call at night. They are harmless and beneficial (eating mosquitoes).
Monitor lizards
Occasionally, larger monitor lizards can be seen in the interior areas. They are shy and pose no threat to humans.
Birds
Various seabirds, egrets, and small songbirds can be seen on the islands. Gili Meno has a bird park with tropical species in captivity (though opinions vary on the welfare of such facilities).
Insects
Mosquitoes are the main nuisance insect. Use repellent in the evenings. Sandflies can bite on some beaches. Other insects include colourful butterflies, dragonflies, and the occasional giant bee or hornet (rarely aggressive).
Gili Meno Turtle Sanctuary
The Gili Meno Turtle Sanctuary is a community-run conservation project that rescues injured and sick sea turtles, rehabilitates them, and releases them back into the ocean. Visitors can see turtles at various stages of recovery and learn about threats facing these endangered animals. Entry is free but donations are welcomed and directly support the work. A visit here is educational and genuinely impactful.
Gili Eco Trust
The Gili Eco Trust is an environmental NGO on Trawangan that runs reef restoration projects, plastic waste reduction, and horse welfare programmes. Divers can participate in their reef restoration by transplanting coral fragments. Volunteers and donations are always welcome.
Responsible wildlife viewing
Every creature you encounter on the Gilis deserves respect:
- Do not touch or chase marine life
- Do not feed fish, turtles, or any wildlife
- Do not buy products made from marine animals (shells, coral, turtle products)
- Use reef-safe sunscreen to protect the coral
- Report injured or distressed animals to dive shops or turtle sanctuary staff
- Take only photos, leave only bubbles
The biodiversity of the Gili Islands is a privilege to experience and a responsibility to protect. Leave the ecosystem better than you found it, and future visitors (and the animals) will thank you.