Nudi Falls

Nudi Falls is one of the most celebrated nudibranch diving sites in the world — and in the Lembeh Strait, which is already the global epicentre of nudibranch diversity, that is a significant distinction. Located in the northern section of the strait in North Sulawesi, Indonesia, the site is built around a small vertical rock wall descending to about 27 metres, with a sand slope and rubble channel below. The name has a precise origin: diver bubbles rising along the wall sometimes dislodge nudibranchs from above, causing them to drift downward — hence, “Nudi Falls.”

Overview

The site’s defining feature is the vertical rock wall, which is encrusted with ascidians, sponges, and soft corals that provide feeding habitat for an exceptional density and variety of nudibranchs. Below the wall, the terrain transitions to a rubble channel with soft corals, then opens onto a sloping sandy muck zone typical of the northern strait. This combination of wall, rubble, and sand supports one of the broadest species ranges of any single site in the strait. Lembeh Resort’s dive team considers it “usually the most nudibranch-rich site in the Strait.” Visibility runs 8–15 metres. Currents can be light to moderate. Water temperature averages 26–29°C year-round.

Site Information

• Location: Lembeh Strait, North Sulawesi, Indonesia
• Entry Type: Boat dive
• Site Type: Wall dive
• Difficulty Level: Intermediate
• Maximum Depth: 27 meters
• Typical Visibility: 8–15 metres (25–50 feet)
• Current: Light to moderate; occasionally stronger
• Best Time: Year-round; October to May for calmest seas

Marine Life

The wall itself is the primary nudibranch habitat. Chromodorids are abundant — including Ardeadoris egretta and other striking species; Nembrotha, Dotto, and Jalonus varieties are also documented here, and Lembeh Resort lists over a dozen species regularly photographed on the wall face. Aeolid nudibranchs colonise hydroid patches on the wall and in the rubble below. Beyond nudibranchs, the sand slope produces robust ghost pipefish, wonderpus, and flamboyant cuttlefish. Rhinopias and harlequin shrimp have been reported in the rubble channel. Pygmy seahorses have been found at this site. Frogfish are distributed across the rubble zones. No site-specific marine life reports were available for garden eels or species not listed above — the description reflects what sources have specifically confirmed at this site.

Dive Profile

Descend to the wall base in 15–20 metres and work upward along the wall face, examining every sponge patch and ascidian colony for feeding nudibranchs. Then transition to the rubble channel for rhinopias and harlequin shrimp if present. The sand slope shallower than 15 metres hosts muck critters and can be covered during ascent. Reserve enough air for a thorough safety stop in the productive 5-metre zone. Night dives here are popular and productive — conditions and operator offerings permitting.

Entry and Exit

Access by banca boat; Lembeh Resort describes a 7-minute boat ride. Entry via back roll or giant stride. Follow your guide’s direction along the wall then to the slope. Surface with SMB deployed.

Tips and Recommendations

• A nudibranch identification card (waterproof) adds significant value here — the diversity is large enough that many species will be unfamiliar even to experienced Lembeh visitors
• Work the wall face slowly and examine every square centimetre of sponge and ascidian growth before moving on — nudibranchs are often sitting in plain sight but camouflaged against their food source
• Ask your guide before descent which families are currently most abundant; seasonal patterns affect which species predominate
• A 100mm macro or supermacro dioptre setup is essential; many of the most interesting species here are under 15 mm in length
• Bring a focus or video light — the wall can be shadowed and accurate colour reproduction requires supplemental lighting

Safety Considerations

Intermediate difficulty is warranted by the mild current potential in the northern strait section. If current picks up during the dive, ascend the slope slightly and use the topography as shelter rather than fighting it in the open. Standard Lembeh precautions apply: no touching, careful buoyancy on the sponge-covered wall. Blue-ringed octopus are present throughout the strait. Carry an SMB.

Photography

Nudi Falls is arguably the finest nudibranch photography site in Southeast Asia. Chromodorids against dark ascidian backgrounds create high-contrast images. Aeolids in profile against the wall surface or backlit water are classic supermacro subjects. Wet dioptre attachments (+5 or +10 close-up lenses) allow extreme magnification of gill plumes and rhinophores. A diffused strobe setup reduces harsh shadows in the intricate wall surface. Allow one full dive per genus family to do justice to the variety here.

Sources: Lembeh Resort – Nudi Falls, PADI – Nudi Falls, Starfish – Lembeh Dive Sites, NAD-Lembeh – Nightdiving Nudi Falls, Infinite Blue Dive Travel – 15 Best Lembeh Sites. Last updated 2026-06-14.