Unicorn's Playground is one of the lesser-known Cocos dive sites, described in Underwater Australasia's 'Destination Cocos (Keeling) Islands' feature on a trip with Cocos Dive. The article characterises it as an unspoiled coral garden with abundant fish: parrotfish, angelfish, butterflyfish and surgeonfish swarming the coral, and dart gobies and fire gobies hovering over their burrows in the sand. The name likely refers to unicornfish, surgeonfish with a horn-like projection on the forehead that are common on Cocos reefs, although the origin is not documented.

Based on the description it is a relaxed reef dive suited to all certified divers, the kind of site used as a second dive of the day. The fire gobies and dart gobies make it rewarding for macro photographers, who can spend the dive lying off the sand edge waiting for the gobies to rise, while wide-angle shooters will enjoy the coral scenery. Visibility is typically 20–30 m.

As with all Cocos sites, the remoteness and absence of dive pressure keep the coral in good condition. Ask Cocos Dive for the site by name; operator site names change over time, so it may now be known by another name. Because Cocos Dive runs only one or two boats and caps groups at 10 divers, sites like this see very few visitors in a year, and the reef shows it: broken coral and fishing debris are rare, and fish are unafraid of divers.

Good buoyancy keeps it that way.

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 site's position is not published; it is visited only as part of a Cocos Dive day trip when the guide chooses it for the conditions.

No shore access.

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.

The exposure of this site is not documented; Cocos Dive schedules it according to wind and tide.

Follow the guide's briefing. Typically a gentle coral-garden dive: descend on the reef, meander through the coral heads at a comfortable depth, look closely at the sand edges for dart and fire gobies, and finish with a safety stop in the shallows.

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.