Nudi Retreat

Nudi Retreat is a nudibranch-focused muck dive site in the northern section of the Lembeh Strait, North Sulawesi, Indonesia. Situated in close proximity to its companion site Nudi Falls, Nudi Retreat is set in a small protected cove with an adjacent soft coral wall — giving it both muck-slope and structural elements. It presents a somewhat different character from Nudi Falls, with a shallower profile capping at 20 metres and a species composition that complements rather than duplicates what divers see at Nudi Falls. Operators frequently pair the two sites on the same day.

Overview

Nudi Retreat’s small cove setting and adjacent soft coral wall create a different nudibranch assemblage than the exposed wall at Nudi Falls. The hydroid-covered rubble patches and low-profile sponge communities support aeolid nudibranchs in good density. The shallow maximum depth (20 metres) means extended bottom times, making this a good site for methodical, slow-paced macro exploration. Visibility is 8–15 metres; currents are light to moderate. Water temperature is stable at 26–29°C.

Site Information

• Location: Lembeh Strait, North Sulawesi, Indonesia
• Entry Type: Boat dive
• Site Type: Muck dive
• Difficulty Level: Intermediate
• Maximum Depth: 20 meters
• Typical Visibility: 8–15 meters (25–50 feet)
• Current: Light to moderate
• Best Time: Year-round; October to May for calmest conditions

Marine Life

Nudi Retreat is particularly productive for aeolid nudibranchs, which prey on hydroids — the hydroid-covered rubble patches at this site provide the feeding habitat these species require. Various aeolid species are documented in good numbers. Dorid nudibranchs feeding on sponge growth add chromatic variety. Confirmed additional species at this site include: Pegasus sea moths, Coleman shrimps, blue-ringed octopus, flamboyant cuttlefish, scorpionfish, anemonefish, and boxer crabs (per starfish.ch and dive-the-world.com). Cuttlefish are frequently spotted hunting near the rubble, and frogfish species occupy positions among encrusted debris. The sandy inter-rubble zones produce mantis shrimp and sand-dwelling gobies with commensal shrimps. No species are attributed beyond what sources have specifically confirmed at this site.

Dive Profile

Work the rubble and hydroid zones between 8 and 18 meters. Hydroid colonies are the key habitat feature to search — locate a large hydroid stand and examine every branch carefully before moving on. The shallower upper sections of the site above 10 meters have the highest hydroid density and thus the most productive aeolid nudibranch hunting. Unlike deeper sites in the strait, the 20-meter maximum allows very generous bottom times of 60 minutes or more, rewarding the patient diver who wants to cover the same ground multiple times.

Entry and Exit

Access by banca boat. Entry via back roll or giant stride. Navigate with your guide along the rubble zones. Surface with SMB.

Tips and Recommendations

• Nudi Retreat pairs naturally with Nudi Falls for a full nudibranch-focused dive day — plan a surface interval between them and approach each with fresh eyes
• Hydroid stands require careful examination — aeolid nudibranchs feeding on hydroids are often the same colour as their prey and require close scrutiny to detect
• The shallower profile here makes it a better site than Nudi Falls for photography lighting, as surface light penetrates more evenly throughout the dive zone
• Ask your guide to note the nudibranch species they find — experienced Lembeh guides can identify nudibranchs on sight that most divers cannot distinguish from their surroundings
• Multiple passes over the same section of rubble on a single dive frequently reveal additional species missed the first time

Safety Considerations

Intermediate difficulty is appropriate due to mild current potential and the need for solid buoyancy control on the hydroid-covered bottom. Hydroids and certain nudibranchs can cause skin irritation on contact — do not touch anything, and avoid dragging equipment across hydroid stands. Standard blue-ringed octopus awareness applies throughout Lembeh. Carry an SMB.

Photography

The hydroid habitat at Nudi Retreat creates distinctive photographic backdrops — aeolid nudibranchs photographed against the branching hydroid structure produce complex, layered images that differ from the clean-sand shots typical of other Lembeh sites. Supermacro with a dioptre attachment reveals extraordinary detail in the gill plumes and preference markings of aeolid species. A diffused strobe or ring flash reduces harsh shadows in the intricate hydroid structure. The shallower depth improves ambient light availability throughout the dive.

Sources: NAD-Lembeh Resort Diving, Starfish – Lembeh Dive Sites, Dive-the-World – Lembeh Diving, ZuBlu – Lembeh Strait, Lembeh Resort – Muck Diving Guide. Last updated 2026-06-14.