Is the underwater waterfall safe? Can you swim in it?

Nobody enters the water to see it, so the question of swimming in it does not arise. The underwater waterfall is sand sliding down a slope beyond the reef, seen from a helicopter. There is nothing to swim to, no current pulling anything down, no hole. The activity is a scenic flight, and the safety questions worth asking are aviation ones: seats allocated by weight, weather holds, passports at the gate. The sea in Mauritius is safe where the beaches and hotels flag it, inside the reef; the risk is at the passes and outside.

Swim in it?No — nothing to swim to

What is thereA sand slope in open water

The activityA 35–45 min flight

SeatingBy weight, for balance

WeatherHeld, rescheduled or refunded

LagoonsCalm inside the reef

The thing itself is not a hazard

I get asked whether the underwater waterfall pulls swimmers down, whether there are sharks at the bottom, whether it is safe to be near. The honest answer is that there is no “it” to be near. Off the tip of Le Morne the shelf, no deeper than about 150 m, ends and the seabed drops to more than 4,000 m. Sand and silt slide down that slope. From above, the plume looks like a waterfall. At sea level it looks like the sea. Nothing is falling, nothing is sucking, and the water column is ordinary open ocean beyond a reef. What is at the bottom is a slope of sand; see how deep it is. Whether it is real at all is on is the underwater waterfall real.

Nobody swims out to it, because there is nothing to arrive at and it is beyond the reef in water that has current and swell. Nobody dives it. Nobody should try. The people who see it are sitting in an aircraft with the doors on and a headset over their ears.

The flight, which is the real activity

Six seasons briefing passengers on the airport apron taught me that the things people worry about and the things that actually stop a flight are different lists. What actually matters:

Weight and seating. Helicopters carry four or six passengers and are balanced by putting the right weights in the right seats. The operator asks for weights at booking. Declare them honestly; nobody is judging, and a wrong number is the one thing that genuinely causes a problem on the day. A party can be split across two aircraft.
Weather. Cloud on the Black River Gorges holds the airport loop. The operator decides, reschedules or refunds. Nobody is flown into cloud to keep a slot. The wet season, December to April, and cyclone season, January to March, see the most holds.
Passport. The helipad is airside. Gate 3 checks it. Bring it.
Doors, headsets, briefing. Doors stay on. Headsets are provided and the briefing covers boarding, seatbelts and the rotor. Commentary in English or French.
Who should not fly. The operators exclude pregnancy, back problems and anyone prone to motion sickness on the helicopters; the seaplane adds heart problems, vertigo, under-7s and anyone over 105 kg. Those exclusions are the operator’s and they are firm.

Philipp from Austria wrote that “the pilot was super professional and friendly”, and that is the standard I saw. What to have with you at the gate is on what to bring.

Is the sea in Mauritius safe?

Since the search that brought you here usually bundles this in: yes, where you are meant to swim. Mauritius is ringed by reef, and the lagoons inside it are shallow and calm; that is where the beaches are and where the hotels flag safe water. The risk is at the reef passes and outside the reef, where currents run and swell breaks, and during big south-westerly swells even the Le Morne lagoon gets lively. Sharks are essentially absent inside the lagoons. Jellyfish turn up seasonally; ask at the beach. Swim where the flags say to, and you will be fine. None of this has anything to do with the illusion, which nobody enters the water to see.

If you want a day on the water at Le Morne, the catamaran from the Le Morne Anglers’ Club jetty in La Gaulette carries life jackets, a first-aid kit and a crew, sails inside the reef to Tamarin Bay and back past Crystal Rock and Île aux Bénitiers, and does not chase the dolphins the way the speedboats do. Christopher from France put it as “unlike speedboats, the catamaran doesn’t harass dolphins”. See the catamaran review.

The Le Morne lagoon inside the reef, calm and shallow

Insider tip

The most common thing that stops a passenger flying is not weather. It is a passport left in the hotel safe. The second is a weight declared low. Fix both before you leave the hotel.

Check dates on the flight

The 40-minute airport flight, five seats, doors on, headsets, one or two orbits off Le Morne.

Check dates on the underwater waterfall helicopter flight

Free cancellation up to 24 hours before departure on most tours — book now, decide later.

Frequently asked questions

Is it safe to swim in the underwater waterfall?

There is nothing to swim in. The underwater waterfall is sand sliding down a slope beyond the reef, seen from the air; at sea level it is open ocean with current and swell, and nobody goes out to it. The lagoons inside the reef are where you swim.

Are there sharks at the underwater waterfall?

It is open ocean off a reef, so the same wildlife as any Indian Ocean drop-off. It is not a place anyone swims. Inside the Mauritius lagoons, where people do swim, sharks are essentially absent.

Is the helicopter tour in Mauritius safe?

Licensed pilots, doors on, headsets, briefing, seats balanced by weight, and flights held rather than flown in cloud. The exclusions, pregnancy, back problems and motion sickness, are the operator’s. Detail on helicopter tours.

What is at the bottom of the underwater waterfall?

A slope of sand running down from a shelf about 150 m deep into a drop-off of more than 4,000 m. No cave, no hole, no waterfall. See how deep it is.

Is the sea in Mauritius safe for swimming?

Inside the reef, yes, at flagged beaches. The passes and the open sea beyond the reef have currents and swell. Jellyfish appear seasonally. Ask at the beach and swim where the flags say.