Belongas Bay diving is the wildest thing you can do underwater in Lombok. The bay sits on the island's remote south coast, and the pinnacles just offshore pull in schooling hammerhead sharks. The water is cooler than the rest of Indonesia, the surge is heavy and the current can run hard. This guide covers the dive sites, the hammerhead season, the conditions and the experience you need before you book.

Where is Belongas Bay?

Belongas Bay is a deep, cliff-lined bay on the south west coast of Lombok, in Indonesia's West Nusa Tenggara province. Dive boats leave from the bay and reach the famous offshore pinnacles in roughly 15 to 30 minutes. Most visiting divers book the trip through a dive center in Kuta Lombok.

The coast here looks nothing like the calm, shallow reefs of the Gili Islands. Cliffs drop straight into open water. The Indian Ocean swell arrives with nothing to block it. That exposure is exactly why the diving is so good, and why trips get cancelled when the sea is up.

Getting there is simple enough. Fly into Lombok International Airport at Praya, then drive south to Kuta, which takes about 30 minutes. From Kuta it is a road transfer west to the bay, on winding roads through hills and villages. Your dive center handles the transfer and the boat as one package, so you rarely need to organise anything yourself.

Photo by Afif Ramdhasuma

The Magnet: Lombok's hammerhead pinnacle

The Magnet is an offshore rock that rises from around 80 metres to just above the surface. Divers work the top 20 to 25 metres of it and wait in the blue for scalloped hammerheads. Strong current, sudden downcurrents and heavy surge make it one of the most demanding dives in Indonesia.

The dive starts fast. Boats drop you close to the rock and you enter negatively buoyant, then descend quickly to about 15 metres to get below the worst of the surge. Waves break on the pinnacle above you, so the top few metres are a washing machine. Once you are down, you tuck in beside the rock, hold your position and watch the open water.

That waiting game is the whole point. Hammerheads pass in the blue, often below the divers, sometimes in schools. Nothing is guaranteed. Some days the sharks do not show and you finish the dive with tuna, mackerel and a lot of adrenaline instead.

The other dive sites in Belongas Bay

Belongas Bay is more than one pinnacle. The Cathedral and Gili Sarang are the two other big-water sites, both for experienced divers. Inside the bay a set of sheltered sites stays diveable when the outside is rough, with soft corals, macro life and easy conditions. Most trips run two or three dives.

The Cathedral

The Cathedral is a steep wall at a small island called Anak Ewok. It drops to about 50 metres. Waves fill the top five metres, so entries and exits need timing and a calm head. Reef sharks, tuna, mackerel and barracuda patrol the wall, and eagle rays sometimes pass in groups.

Gili Sarang

Gili Sarang sits closer to shore than the Magnet, but it is still open sea. Pinnacles rise from around 40 metres. Giant trevally, mackerel and reef sharks work the current lines. On calm days with mild current, guides slow down and look for nudibranchs and other small life on the rock.

The sheltered sites inside the bay

Coral Garden is the friendly one. It sits at about 25 metres, out of the big waves, with soft corals in yellow, orange and purple, gorgonian fans and anemones. Wollis Pinnacle runs from 5 to 20 metres over sand and holds nudibranchs, frogfish and ribbon eels. Boulder City is a wall to 30 metres with Napoleon wrasse and sweetlips.

When to dive Belongas Bay for hammerheads

Hammerheads can school around the Magnet from late June to early November, and sightings are most frequent from August to November. That window is also when the surface conditions are hardest. Big swell cancels boats, so give yourself several days in the area rather than one.

Water temperature is the other surprise. Thermoclines drop it to around 21 to 24 degrees at depth, which is cold for Indonesia. A 5 mm wetsuit is the sensible minimum, and a hood or hooded vest makes the safety stop far more comfortable.

Outside the hammerhead season the bay still dives well, with calmer seas and better visibility on the inner sites. If you are planning a wider trip, our region by region season guide for Indonesia shows how South Lombok fits alongside Komodo, Bali and Raja Ampat.

What you see underwater

Belongas Bay is a big-fish destination. Scalloped hammerheads are the headline, and behind them come schooling barracuda, tuna, giant trevally and Spanish mackerel. White-tip, black-tip and grey reef sharks cruise the walls, and eagle rays and mobula rays pass through. The inner bay adds macro life on coral and sand.

Photo by Ekaterina Zlotnikova

Barracuda hang in tight, slow-moving groups in the blue. Trevally and mackerel move differently. They rip past in bursts, hunting through clouds of small fish that gather around the pinnacles.

Photo by Lufi Matondang

Those bait schools are the reason the predators keep coming back. Current hits the rock, food piles up, and everything larger follows. If you want to compare South Lombok with the other Indonesian hammerhead spots, read our guide to hammerhead shark diving in Indonesia.

Who Belongas Bay diving is for

The outer sites suit experienced divers only. Guides ask for an advanced certification and usually 50 to 100 logged dives, depending on the season and the forecast. You need to be comfortable with negative entries, fast descents, strong current and cold water at depth, and you must follow the guide exactly.

Bring a surface marker buoy and know how to deploy it. Boats work a big, exposed patch of ocean, and a buoy makes you easy to find. Good buoyancy matters more than anything else here, because you spend the dive holding a position in moving water.

If that does not sound like your kind of day, dive the sheltered sites in the bay instead, or head north. The Gili Islands sit a few hours away and offer warm, calm, turtle-filled reefs with far gentler conditions.

Belongas Bay diving FAQs

Will I definitely see hammerheads at the Magnet?

No. Hammerheads can school around the Magnet from late June to early November, with the best odds from August to November, but sightings are never guaranteed. Plan several dives rather than one.

Is Belongas Bay diving suitable for beginners?

Not the outer sites. The Magnet, the Cathedral and Gili Sarang need an advanced certification and around 50 to 100 logged dives. Newer divers can dive the sheltered sites inside the bay, such as Coral Garden and Wollis Pinnacle.

How cold is the water?

Thermoclines bring it down to about 21 to 24 degrees at depth. Wear at least a 5 mm wetsuit, and add a hood or hooded vest if you feel the cold.

How do I get to Belongas Bay?

Fly into Lombok International Airport at Praya, then drive about 30 minutes to Kuta. Dive centers in Kuta run the road transfer west to the bay and the boat out to the sites as one trip.

What else can I dive in South Lombok?

The south coast has plenty beyond the bay, including sites around Ekas Bay and along the south coast itself. Browse the Scubalo dive site directory to see what each one offers.

Where to book your South Lombok dive trip

Belongas Bay trips run from Kuta Lombok, and the operator you pick matters more here than at an easy reef. Ask about group size, guide experience at the Magnet and the criteria they use to call off a day. Blue Marlin Lombok Kuta, Adventure Divers Lombok and Scuba Froggy all dive the south coast from Kuta and are listed on Scubalo with reviews, contact details and the sites they visit.

Compare more operators across the island in the Scubalo dive center directory, and check conditions, depths and marine life for individual sites in the dive site directory before you commit to a date.