The Manta Service Station is a manta ray cleaning station in the lagoon of the southern atoll, a site where reef mantas come in to have parasites and dead skin removed by small cleaner wrasse. Diveplanit's description of a day's diving puts the station at about 9 m and notes excellent ambient light for photography, and its site list mentions slumbering whitetip reef sharks here as well. The official Cocos tourism snorkelling feature lists a manta ray cleaning station 'in the heart of the lagoon', and Cocos Blue Charters' glass-bottom boat tours visit it.

The dive is about patience. Divers settle low and to the side of the station and wait; mantas circle in, hang over the coral heads with their wings slowly flexing while wrasse pick at them, then glide off and return. Cocos has a resident reef manta population, and Cocos Dive's 'Project Manta' photo-identification work has catalogued individuals by their belly markings; SSI's Edges of Earth feature describes a single encounter with at least ten mantas for 90 minutes on the Cocos rim, which gives a sense of how good manta encounters can be.

Encounters are never guaranteed, and the tide, the time of day and plankton levels all influence whether the mantas are present. The shallow depth allows long bottom times, and the site suits divers of all levels who can hold still and control buoyancy. Snorkellers can watch from the surface when the mantas are shallow.

The exact location is deliberately not published, protecting the animals from unmanaged pressure. Code of conduct: stay low and still, never chase or touch a manta, don't swim over the cleaning station, and keep strobes to a minimum.

Fly to West Island on the twice-weekly Virgin Australia service from Perth (usually routed via Christmas Island; allow 7–10 days on the islands to absorb weather and flight delays). Cocos Dive collects divers from West Island accommodation in the morning (pickup around 8 am, departure about 9 am) and runs its boats from West Island into the lagoon. The cleaning station is in the lagoon; its position is not published and it is reached only on a guided trip.

Cocos Dive and glass-bottom/lagoon-tour operators (e.g. Cocos Blue Charters) include it when conditions and manta activity are right. The boat approaches slowly and anchors or drifts off the station so the mantas are not disturbed.

Cocos has two seasons. The south-east trades blow steadily from roughly April/May to October, often 15–25 knots, which chops up the lagoon and pushes swell onto the eastern and southern outer reefs; divers are then kept to sheltered sites. The doldrum season (November to March/April) brings lighter, variable winds, flatter seas and the widest choice of outer-reef sites, and is the best time to dive, though it is also the tropical cyclone season and squalls pass through.

Inside the lagoon, the main factors are wind chop and tide: strong trades make the crossing rough and stir up sand in the shallows, while calm doldrum days give glassy water and the best visibility. Visibility is usually best around high tide and on the incoming flow; the lagoon is shallow and warm, and a falling tide carries turbid water out of the flats. Mantas are present around Cocos year-round, with encounters depending on tide, plankton and luck rather than a fixed season.

Descend a short distance from the cleaning station and settle on the sand or rubble at about 9 m, low and still, off to one side. Wait for mantas to come in to be cleaned; don't swim over the station or block their approach. Stay put for most of the dive and ascend slowly away from the station.

Cocos Dive (Dieter Gerhard, West Island, operating since 1990) is the only scuba operator on the islands and the only way to dive this site. It runs seasonal two-dive day trips with lunch and a surface interval on Direction Island, maximum 10 divers per trip; sites are chosen on the day according to wind, tide and diver experience. Trips book out well ahead and courses are currently suspended, so arrive certified.

Cocos Blue Charters' glass-bottom boat tours also stop at the manta cleaning station.