Santo's legendary Blue Holes, Vanuatu: Incredible beauty of mysterious freshwater swimming pools

The approach to the Riri Blue Hole is more tranquil – a gentle paddle via traditional dug-out canoe through a silent, mangrove-lined creek tangled with vines. Twenty minutes later, we emerge at the sapphire swimming hole, deserted in the dappled shadows of afternoon. To have a paradise like this to myself seems truly miraculous, and I can't help but think I've stumbled upon Michener's mythical Bali Hai.

Swimming in such a pristine environment is revelatory; but to do so on the back of a horse takes the experience to a whole new level. There are several operators offering beach rides to tourists in Santo and surrounding islands; some, it must be said, take a lackadaisical approach to safety and animal welfare, a not uncommon situation in underdeveloped nations.

For Kiwi expat Megan Jane Lockyer, however, safety is paramount, with as much concern for her beloved horses as her clients. All riders must wear helmets, while light synthetic saddles and bitless bridles ensure minimal pressure for her horses, all of which have suffered ill treatment in the past.

"This is a rescue sanctuary – these horses have all been saved," Megan explains. "Of my 26 horses, only 10 have been rehabilitated to the point where they can be ridden again. I'm not putting them through any more trauma – my horses mean everything to me."

Each horse in Megan's stable has a sad tale to tell, suffering at the hands of the cruel and ignorant. One had been ridden in a bit made from barbed wire, while my four-year-old palomino, Lou Lou, suffered a machete swipe to the eye. With no veterinarian on the island, Megan has to administer all medical, dental and farrier work herself, coping as best she can with limited resources and equipment.

To look at her contented string of ponies, however, you'd never guess of their past suffering. As Megan gives basic instruction before setting out on our two-hour trail ride, I note how fat and shiny her ponies are – the result of organic copra meal (a bi-product of coconuts) in their diet. This, incidentally, is why Santo beef is universally praised for being so succulent – the cows graze among the coconut palms, ensuring plenty of natural oils in their meat.

Lou Lou, I'm warned as I swing into the saddle, loves the water, with a tendency to lie down on the job. "The record is seven times in one ride," Megan laughs. "And that was with me riding her!" Duly noted; and with my phone tucked high into my bra, we set off in a line from the corrals at Lope Lope Lodge, the base for Santo Horse Adventures.

With several inexperienced riders in our group, Megan – who personally leads every trail ride – sets a slow pace along a jungle trail, eagle eyes ensuring everyone is comfortable and secure in the saddle. After about half an hour winding past villages and through dense rainforest, we reach Suranda River, where we pause for more instruction before entering a tunnel cut through the mangroves, fast-flowing with the tidal deluge.

"Follow directly behind me – the tide is coming in and you may get out of your depth," Megan warns. "Hang onto your horse's mane, and let them do their work."

The grins on the first-time riders' faces says it all – it's an incredible experience to feel the power of a horse beneath you, pushing against the resistant current, legs going hell-for-leather as they struggle to keep up with their stablemates. Water baby Lou Lou is in her element, her snorts and splutters sounding uncannily like horsey chuckles – but so far, we've managed to avoid scuba diving.

We still have several more streams to cross, however – and as we reach the beach in front of Lope Lope Lodge, the tide is well and truly at its peak. Once again, we're belly-deep, breakers nipping against the horses' legs as we traverse the bay.

Immediately I feel a change in Lou Lou's demeanour; she's stepping out, joyfully stamping her hooves with a resounding splash. Suddenly, she groans, legs buckling beneath her; I feel myself sinking into the depths, and leap off like a gymnast, snatching my phone and holding it triumphantly above my head as Lou Lou dunks under the waves, head and all.

Fortunately, I land on my feet, roaring with laughter as Lou Lou sheepishly emerges, shaking the salt water from her long lashes. After all, I can't blame her for wanting to throw herself into this balmy ocean – who doesn't enjoy a dip in paradise?

See also: The world's 10 most amazing places to take a swim

See also: This hole is one of the world's most amazing swimming pools

TRIP NOTES:

FLY

Air Vanuatu flies from Sydney to Port Vila three days a week, with onward flights to Santo Espiritu. Air Vanuatu also offers a direct flight from Brisbane to Santo once a week. See airvanuatu.com

STAY

Barrier Beach Resort is a lovely boutique property featuring stylish beachfront villas, about 15 minutes drive from the main town of Luganville, priced from around $256 per night. See barrierbeachresort.com

RIDE

Santo Horse Adventures, including transfers, cost around $90 for adults with $50 pony rides available for children. Phone +678 777 4700, see facebook.com/SantoHorseAdventures

MORE

Traveller.com.au/vanuatu

vanuatutravel.info

Julie Miller was a guest of Vanuatu Tourism and Air Vanuatu.

Five other things to do in Santo:

VISIT CHAMPAGNE BEACH

It takes a good strip of sand to impress Australians – but this privately owned beach on the east coast of Santo is up there with the best. Crystal clear water, champagne powder-fine sand lined with majestic Tanama trees, and docile Santo beef cattle grazing under coconut palms make this well worth a detour.

DINE AT PORT OLRY

Pull up a stool in the sand or swing in a hammock as you enjoy freshly caught fish at one of three rustic beachfront restaurants. Many diners come here specifically for the coconut crab – but after I indulged, I discovered they are in fact an endangered species (hence racking me with guilt!) Check out the cute treehouse accommodation on the beach as well.

SNORKEL MILLION DOLLAR POINT

After World War II, relics such as machinery, vehicle and boats were dumped offshore by American servicemen, creating an artificial reef of the most curious kind. Close enough to the beach for snorkellers as well as divers.

DIVE THE COOLIDGE

Santo's other famous dive site is the wreck of SS President Coolidge, one of the largest and most accessible wrecks in the world. The 22,000-tonne luxury passenger liner was commandeered as a WWII troop carrier but hit a mine then the reef in 1942, landing on its stern.

LISTEN TO WATER MUSIC

At the Leweton Cultural Village near Luganville, women from the northern Banks group of islands give demonstrations of "magical water music", creating sounds of nature by slapping and drumming water in a swimming pool. Fascinating, strange and surprisingly entertaining.