Belongas Bay on south Lombok delivers Indonesia's most accessible scalloped hammerhead shark encounters, plus the dramatic underwater pinnacles of The Magnet and The Cathedral. This is an advanced-only destination with strong currents (3–4 knots), 18–35m depths, and big-water conditions — Open Water divers should not attempt these sites. Two operators run dedicated Belongas trips: Dive Zone Lombok from Kuta and Lombok Dive Centre from Mataram. Day trips run 1.6–2.0M IDR per diver including transfers; the prime hammerhead season is July–October.
# Diving Belongas Bay: Lombok's Big-Water Shark Destination
Belongas Bay sits on Lombok's exposed south-west coast where the Indian Ocean meets a series of dramatic underwater pinnacles. It is the only realistic destination in Lombok where you can dive with scalloped hammerhead sharks, and one of the few places in Indonesia outside the Komodo and Banda Sea areas where you can do so without paying liveaboard prices.
This is not a beginner destination. If you've just earned your Open Water certificate, do your first 30 dives somewhere else and come back. If you have your AOW with deep specialty and 50+ logged dives, Belongas is one of the best diving experiences in Indonesia.
Three sites carry the reputation:
1. The Magnet — a single pinnacle rising from 35m to 8m below the surface, exposed to powerful Indian Ocean currents. Scalloped hammerhead schools (10–80 individuals) cruise the deeper face in season. Grey reef sharks, eagle rays, mola mola, and large schools of trevally are routine.
2. The Cathedral — a series of pinnacles and overhead swim-throughs. Bigger fish, dramatic topography, and an unmistakable cathedral-vault feel as the morning sun streams through the holes in the rock at 18–25m depth.
3. Belongas village reef sites — sheltered, beginner-friendly sites used as warm-up dives or backup when conditions at The Magnet aren't safe.
The hammerheads are the headline. The Cathedral is the dive that makes you remember why you became a diver.
Scalloped hammerheads (Sphyrna lewini) school at The Magnet during the dry season, particularly July through October, when cool upwellings push along the south coast and bring nutrient-rich water across the pinnacles. The sharks gather in the cooler water at 25–32m depth.
A typical successful encounter:
Sighting rate is realistic but not guaranteed. In peak season (August–October) operators report success on roughly 60–70% of trips. In shoulder months (June, November) closer to 30–40%. Pay-to-dive trips that promise guaranteed hammerheads should be treated with suspicion — nobody can guarantee wild pelagic encounters.
Belongas itself is a small fishing village with no dedicated dive infrastructure. All Belongas diving is run as day-trip or liveaboard from outside operators. The two with serious local knowledge:
Dive Zone Lombok (PADI 5-star, based in Kuta): The most experienced operator on Belongas. Run weekly trips throughout dry season, multi-day liveaboard packages July–October, dedicated hammerhead expedition weeks in September. Strict experience verification. Mid-to-premium pricing.
Lombok Dive Centre (PADI, based in Mataram): Smaller operator, runs Belongas trips on demand and as part of multi-site South Lombok expeditions. Less polished than Dive Zone but reputable.
A handful of operators on the Gili Islands also run rare Belongas day trips on demand — these are typically 2.5M+ IDR per diver due to the longer transfer and worth doing only if you can't get to Kuta.
A standard Dive Zone Lombok Belongas day:
Compare to Komodo liveaboards (15–25M IDR for 4 nights) and Belongas is excellent value for advanced shark diving.
Topography: a single pinnacle rising from a 40m sand floor, peaking at 8m below the surface. South face is the deep wall. North face is gentler. The currents wrap around the pinnacle and create a defined eddy zone on the lee side.
Plan: descend on the down-current side using the line, hook in at 25–28m on the south face, wait. Schools approach from deeper water and pass at 30–32m, sometimes ascending to 25m. Bottom time 35–40 minutes max.
Marine life: scalloped hammerheads (school), grey reef sharks (resident), white-tip reef sharks (resident), eagle rays, schooling jacks, barracuda, occasional mola mola in cool water.
Topography: a cluster of pinnacles with multiple swim-throughs at 18–25m, including one major overhead chamber that gives the site its name. Light streams through the gaps in the rock and creates a vaulted-cathedral atmosphere.
Plan: descend on the line, follow the guide through the swim-throughs, exit on the down-current side. Bottom time 40–45 minutes.
Marine life: Soft coral cover on the pinnacle walls, schooling glassfish in the chambers, white-tip reef sharks resting on the sand, occasional turtle, occasional mola mola.
June–October: Peak. Cool upwellings present, hammerheads active, water 24–26°C (cooler than the Gilis). Visibility 20–30m.
July–August: Hammerhead season starts but swell can cancel trips. Plan extra days.
September: The single best month. Stable seas, peak shark activity, post-school-holiday quiet.
October: Excellent, often slightly warmer water and good visibility.
November–May: Off-season. Sea is rougher, hammerheads less consistent, many operators don't run scheduled trips.
Belongas is genuinely advanced diving. Reputable operators will:
The decompression chamber is in Mataram, roughly 3 hours by road. The boat itself usually carries oxygen but not a stretcher. Travel insurance with diving evacuation cover is mandatory, not optional.
A full south Lombok dive itinerary might look like:
This gives you two shots at hammerheads and a full survey of south Lombok's diving. Total cost roughly 5–7M IDR in fun dive fees plus 800k–1.2M IDR per night accommodation in Kuta.
Belongas Bay is a 90-minute drive from Kuta (south Lombok) along bumpy roads via Mawi and Sekotong. Most divers book a full-day trip with Dive Zone Lombok or Lombok Dive Centre, who handle the early-morning pickup, boat charter, and return transfer. Self-driving is possible but the boat departure point at Belongas village is genuinely remote — expect rough roads. International airport (LOP) is 90 minutes north of Kuta; allow at least one prior day in Kuta to acclimate.
Belongas Bay vs the Gili Trio: completely different style. The Gilis are easy beach diving with turtles and reef life; Belongas is big-water, advanced-only, and pelagic-focused with hammerheads, mola mola, and grey reef sharks. Belongas vs Komodo: Komodo has more famous mantas and bigger pelagic action but costs 3–5x more. Belongas vs Bali Crystal Bay: both have mola mola in season, but Belongas adds the hammerhead encounter — and it's significantly cheaper. Belongas is the value pick for advanced divers wanting Indonesian shark and pelagic diving without Komodo's price tag.