The Rip is Australia's best-known drift snorkel and the one experience almost every Cocos visitor seeks out. At the eastern end of Direction Island a narrow channel cuts through the reef, and ocean water floods through it continuously into the lagoon, creating what the official tourism site calls a natural drift snorkel known worldwide. Snorkellers enter at the seaward end and are carried through a coral-lined channel a few metres deep before being released into the calm, shallow lagoon – a ride likened by Diveplanit to a waterslide.

The channel is full of fish that sit in the flow: humphead parrotfish, Napoleon (humphead) wrasse, bluefin trevally, groupers and snapper, with reef sharks – blacktips, whitetips and grey reef sharks – cruising or holding position in the current. Barracuda to 1.5 m, morays, turtles, angelfish, butterflyfish and neon damsels are all regularly seen, and the coral cover along the walls is high – SSI's feature estimated about 70%. Divers sometimes run it on scuba, and Cocos Dive has recorded mantas passing through.

A safety rope is strung in the channel so snorkellers can stop and hang on to watch the sharks. The edges are calmer than the centre, making it manageable for competent swimmers, but the current is strong, especially on high tides, and there are no lifeguards. Direction Island itself adds to the day: Cossies Beach on the lagoon side has been voted Australia's best beach, and the island carries history from the Eastern Extension cable station (from 1901) and the Emden landing party of 1914.

The waters around The Rip are one of two small inshore National Park (green) zones in the marine park, so no fishing is allowed. Most people make several runs, seeing more each time.

The public ferry runs from West Island (and Home Island) to Direction Island twice a week, on Thursdays and Saturdays; the return fare is $5 per person, cash on board, and the return boat leaves Direction Island in the early afternoon (around 2 pm – be at the jetty or be stranded). Check the current Shire timetable on arrival. From the Direction Island jetty follow the track east about 10 minutes to the viewing platform over The Rip, or turn toward the beach at the last picnic table for the easiest entry.

Walk up the shore to the seaward end, enter, drift through the channel and exit on the lagoon beach, then walk back and repeat. Cocos Dive's Monday-morning sea-scooter tours and local skippers can drop snorkellers at the top of the channel and collect them in the lagoon.

The Rip is a tidal channel: ocean water pours through it into the lagoon, and the speed depends on the tide, the swell and the moon phase – Dive Pacific reports up to 4 knots. High and incoming tides, spring tides around full and new moon, and big south-east swell pushing water over the reef all make it faster; low tide gives the slowest flow and suits weaker swimmers and those wanting to linger. In strong trade winds (April–October) the surface is choppy and the entry rougher, but the snorkel still runs; the doldrum season (November–April) gives the calmest water.

Visibility is best on the incoming tide. Plan the day around the ferry times, which fix when you can be there.

Walk to the seaward end of the channel, enter from the shore and relax face-down; let the current carry you through, holding the safety rope to stop and look if needed. Stay near the channel edges for calmer water, or in the centre for the full ride. Once in the lagoon the flow slackens – swim to the beach, walk back and repeat.

Never swim against the current.

Mostly self-guided via the public ferry. Cocos Dive runs sea-scooter snorkel tours at The Rip most Monday mornings (limited places) and dives the channel on its trips; local skippers and lagoon tours offer drop-off and pickup.