Aer Bajo

Aer Bajo is a black sand muck dive site on the east coast of Lembeh Island in the northern Lembeh Strait, North Sulawesi, Indonesia. Located on the Lembeh Island side of the strait, the site has a fairly flat sandy slope from the shallows to about 20–22 metres. It is rated beginner-friendly and is described by operators as a great site for night dives given its protected, sheltered position and typically minimal current. The name derives from the Indonesian words for “water” (aer, an older spelling of “air”) and “bajo” meaning “low” or “below” — a likely reference to the site’s coastal position.

Overview

Aer Bajo presents classic Lembeh muck: volcanic black sand and rubble slope on the Lembeh Island coast, with the most productive critter zones concentrated in the 8–20 metre range. The terrain is described as “super fun bottom topography” by operators, featuring a flat sandy expanse punctuated by low rubble patches and scattered debris. Currents are rarely significant here. Visibility runs 8–15 metres. Water temperature is stable at 26–29°C year-round.

Site Information

• Location: Lembeh Strait, North Sulawesi, Indonesia (east coast of Lembeh Island)
• Entry Type: Boat dive
• Site Type: Muck dive
• Difficulty Level: Beginner
• Maximum Depth: 22 meters
• Typical Visibility: 8–15 metres (25–50 feet)
• Current: Light; well-sheltered; minimal tidal influence
• Best Time: Year-round; excellent for night dives

Marine Life

Confirmed species at Aer Bajo include: coconut octopus, mimic octopus, blue-ringed octopus, and long-armed octopus; frogfish; Ambon scorpionfish; flamboyant cuttlefish; seahorses (curious, common, tawny, and pipefish seahorse varieties noted by operators); garden eels retreating into the sand; snake eels; and nudibranchs. No additional species are attributed beyond these confirmed records.

Dive Profile

Work the slope between 5 and 20 metres, paying attention to the flat sandy expanses where garden eels and sand-dwelling species congregate, and to the rubble-sand interfaces for frogfish and nudibranchs. The site’s beginner rating reflects the manageable depth, minimal current, and straightforward topography. Beginners will find this an excellent site for developing muck diving techniques — slow movement, precise buoyancy, and detailed observation — without the added challenges of current or depth. Night dives follow the same slope profile; operators describe Aer Bajo as one of the better sheltered night dive options in the northern strait.

Entry and Exit

Access by banca boat. Entry via back roll or giant stride. Navigation follows the slope contour under guide direction. Surface with SMB deployed for boat pickup.

Tips and Recommendations

• Garden eels in the deeper sandy sections retreat rapidly when approached from above — hover 3–4 metres above the slope and observe before attempting to get closer
• Ask your guide about the best rubble patches for Ambon scorpionfish and frogfish at the current time; the animals move but guides track their positions
• Aer Bajo is excellent for beginners to develop the muck diving eye — the relatively open sand habitat makes movement more visible than at dense rubble sites
• The site’s calm, sheltered conditions make it a reliable fall-back on windier days when more exposed northern sites have worsened conditions
• Night dive operators note the site’s minimal current as a key advantage for night diving; the sheltered position keeps conditions stable after dark

Safety Considerations

Aer Bajo is one of the most beginner-accessible sites in the northern Lembeh Strait. The main hazard is the standard Lembeh concern of venomous critters — blue-ringed octopus and Ambon scorpionfish are both present at this site. Do not handle any marine life. Maintain careful buoyancy to avoid silt disturbance. Carry an SMB.

Photography

Aer Bajo’s open sandy habitat offers clean backgrounds for seahorse and garden eel photography. Garden eels in the sand are a unique supermacro opportunity if approached with patience — hover high and descend slowly. Octopus species in multiple varieties make for excellent behaviour sequences, particularly coconut octopus manipulating shells as portable shelter. Ambon scorpionfish with their extraordinary hairy-frond appearance are compelling macro subjects under a focus light. The site’s calm conditions and minimal current are an asset for video work.

Sources: Lembeh Resort – Best Dive Sites North Sulawesi, ZuBlu – Lembeh Strait, Infinite Blue Dive Travel – 15 Best Lembeh Sites, Starfish – Lembeh Dive Sites, Underwater Photography Guide – Lembeh. Last updated 2026-06-14.