The moment a green sea turtle glides past you at five metres — eyes level with yours, indifferent to your presence, a hundred kilograms of ancient animal going about its morning — you stop thinking about your air consumption. That is the Gili Islands.
These three small islands off northwest Lombok sit inside one of the highest resident sea turtle densities in Indonesian waters. On a normal dive day out of Gili Air you are almost guaranteed at least one encounter. On a good day you stop counting at eight.
Two species, one common question
The Gilis host both green sea turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata). Divers often struggle to tell them apart underwater.
The green turtle is the larger animal — adults reach 100–150 kg with a shell length close to a metre. The shell is smooth and brown-olive, sometimes with warm amber streaks; the head is small and rounded. The name is misleading: the shell is not green. The fat beneath is green, from a lifetime of eating seagrass and algae.
The hawksbill is smaller, rarely exceeding 80 kg. Its shell is more steeply domed, patterned with overlapping scutes in chestnut and amber, and the head narrows to a pointed beak — the “hawk’s bill” — which it uses to extract sponges from reef crevices. You will find hawksbills in tighter coral terrain; green turtles favour open slopes with good algae coverage.
At Turtle Heaven on the north side of Gili Meno you routinely encounter both species on the same dive.
What they are actually doing down there
Most turtle encounters around the Gilis fall into one of three behaviours:
Feeding. Green turtles browse algae from coral heads the way a cow grazes a field — methodically, head down, entirely absorbed. They tear mouthfuls of turf algae from hard substrate, leaving circular bite marks that are easy to spot after they have moved on. Hawksbills are usually picking sponge out of gaps in the reef with that narrow beak.
Resting. Turtles are reptiles. They cannot extract oxygen from water, so they surface to breathe — but between surfacings they wedge themselves into coral overhangs or settle on the sandy bottom and slow their heart rate dramatically to conserve oxygen. A resting turtle can hold its breath for up to seven hours. If you find one tucked under a ledge, it is not trapped — it is asleep. Leave it.
Cleaning. Like reef sharks, turtles use established cleaning stations where wrasse and other small fish pick parasites from their skin and shell. A turtle hovering motionless with its flippers extended and neck stretched is at a cleaner station. Disturbing a cleaning stop means the turtle leaves carrying the parasites that brought it there. Give it a wide berth and watch from a distance.
Where to find them
Turtles are present at almost every dive site around the Gili Islands. Some sites are more reliable than others.
Turtle Heaven on the north side of Gili Meno is the most consistent in the archipelago. Ten to fifteen turtles on a single dive is normal here; the sloping reef between 10 and 22 metres has the algae coverage and coral structure that keeps them resident. Both species feed and rest across the reef.
Hans Reef and Coral Fan Garden on the south side of Gili Air regularly have three or four green turtles feeding on algae-covered boulders in the shallows. Both are Open Water depth, calm current, and easy to access — good first dives for anyone who has never seen a turtle underwater.
Shark Point and Sunset Point around Gili Trawangan hold turtles alongside the resident reef shark population. The deeper sections around 18–25 m sometimes hold hawksbills picking through coral fans.
Turtles are the baseline expectation on our fun dives, not a bonus sighting. If we had a particularly good morning — six turtles on one dive, a hawksbill at the cleaning station, a nesting female spotted on the surface — our guides will tell you before you get in the water.
Male or female? The underwater ID game
Most divers never think to check the gender of the turtles they meet. Once you know what to look for, it takes about two seconds — and it changes how you read the animal’s behaviour completely.
There is one primary marker that works every time: the tail.
Males have a long, thick tail that extends well beyond the rear edge of the shell — sometimes nearly as long as the shell itself. The tail contains the reproductive organ and is the main anatomical difference between the sexes. A male’s tail is impossible to miss once you know you are looking for it.
Females have a short, stubby tail that barely clears the rear of the shell. If you cannot see much tail at all, it is almost certainly a female.
Two secondary cues help confirm:
- Front flipper claws: Males have one enlarged, strongly curved claw on each front flipper, used to grip the female’s shell during mating. Females have smaller, straighter claws.
- Overall size: Females tend to be slightly larger at full maturity, though this is harder to judge without a reference.
Test yourself on your next dive
Before you surface, try to identify the sex of every turtle you encountered. Here is the process:
- Position yourself at the same depth as the turtle, slightly to the side and behind.
- Look at the rear of the shell — does the tail extend clearly beyond the edge, or is it barely there?
- If you got close enough, check the front right flipper for the hooked claw.
► Quick reference: male vs female at a glance
| Feature | Male | Female |
|---|---|---|
| Tail | Long — extends well past shell, often 30–50 cm | Short stub — barely clears the shell edge |
| Front claw | One elongated, hooked claw per front flipper | Shorter, more uniform claws |
| Behaviour | May attempt to mount other turtles during mating season (July–Sept) | Comes ashore at night to nest during nesting season |
In the Gilis, most of the resident turtles you encounter on a day dive are female — males tend to stay in deeper, more open water except during mating season (roughly July through September), when you may see attempted mountings on the reef. If a larger turtle is riding on the back of another and gripping with its front flippers, you have found a mating pair.
How to approach without ruining it
Turtles in the Gilis are calm because they have been treated calmly for many years. That familiarity is a shared resource, and it is possible to spend it.
Don’t touch. Handling turtles stresses them, can disrupt the protective mucus layer on their skin, and is illegal under Indonesian conservation law. It is also the fastest way to turn a relaxed animal into one that bolts every time it sees a diver. We will end a dive early for a guest who grabs a turtle.
Don’t chase. A turtle that has decided to surface for air will surface. If it swims upward, move out of its path and let it pass above you. Following it to the surface turns a five-minute encounter into a three-second one.
Approach from the side, not from above. Come in at depth, slow your fin kicks, and let the turtle notice you on its own terms.
Stay horizontal. The more neutral your position in the water, the longer it stays. Master your buoyancy before you visit sites like Turtle Heaven; dragging on the reef or kicking up silt ends the encounter for the whole group.
A patient diver who watches a green turtle graze for twelve minutes sees more than an excited diver who gets four seconds before it bolts. The slowest approach produces the longest encounter, every time.
Conservation
Both species are IUCN Endangered. Nesting beaches on Gili Meno and Gili Air are monitored during peak nesting season from June through September. If you find fresh tracks or a nest cavity on the beach — typically above the high-water line, the sand disturbed in a circular area about a metre across — leave everything exactly as you found it and report the location to dive centre staff or to the Gili Eco Trust.
The most effective conservation action available to a visiting diver is uncomplicated: don’t touch, don’t chase, and describe what you saw and where to the dive centre when you get back on the boat. Sighting reports build the local knowledge base that guides patrol decisions.
When to come
Year-round. The turtles are resident, not seasonal migrants. Visibility and sea conditions are best between April and November, but green turtles are present on every dive we do regardless of month.
If diving with sea turtles is the main reason you are coming to the Gili Islands — and it is a perfectly good reason to come — get in touch before you arrive. We will put you on the site most likely to deliver based on what our guides reported that morning.