I’ve hit the jackpot. Maybe. Beside me an old fella wearing a ghetto gold medallion and an oversized trucker cap smiles at the table. Next to him a teenager in a garish floral dress eyes up the spinning collection of small wooden horses. Then there’s me, throwing crumpled notes at a game called pica, apparently. I don’t know any of the rules, and I’m not entirely sure what’s going on. But I’m feeling lucky.

Another old chap sidles up to me. “Pica is our version of roulette, but with horses,” he explains. He signals for another rum from the battered wooden shack. “You’ll lose all your money here,” he adds knowledgeably.

“Here” is the Puerto Rico I never knew existed. Although the Caribbean island’s been a favourite of American sunseekers for decades, the exotic blend of Spanish and US culture rarely features on British travellers’ radars. And with new direct flights from Norwegian Air, you can now reach the undiscovered curves of this peachy plot of land for just £270 return.

If that sounds too good to be true, take note from Ricky Martin – Puerto Rico’s most famous export (sorry, J-Lo) – who sits next to me on the flight over, churning through films.

Martin’s big-bucks cashflow may be healthier than the bank balance of most visitors, but that’s not going to stop the budget traveller livin’ la vida loca (sorry) here. Dodge the glitzy mega-resorts and golf courses that litter the north coast of the island, and you could cram a trip to Puerto Rico with lazy strolls through the salsa-soundtracked cobbled streets of Old San Juan. Or hike through the El Yunque rainforest – all 44 square miles of it – where waterfalls and wilderness command full-on adventurer get up. Or bathe in the thermal waters of the island’s oldest colonial town, Coamo, just like Juan Ponce de León, the 15th-century Spanish explorer who was on a mission to discover the elusive Fountain of Youth. And the even-more-elusive cure for sexual impotence.

Vieques is home to small guesthouses, wild horses and glorious sweeps of remote beach. And oh boy, those beaches

Ponce de León was left disappointed (as, presumably, were his lovers), but luckily I’m here with an easier agenda. Beaches. Miles of them. My pica gambling session in the colourful wooden-shack town of Esperanza is just one part of my stay on Vieques, a small island that sits a 30-minute hop by six-seater propeller plane from mainland Puerto Rico. For decades, the land acted as a target practice playground for the US Navy, while local residents were clustered into a precarious semi-safe strip down the middle. After years of local protests, the Navy finally withdrew in 2003, leaving turf that was quickly eyed up for bulldozers and redevelopment. Not so fast: the environmental authorities soon swept in, declaring the former military area (around 70% of the island) a US Fish and Wildlife Refuge. What’s left is a low-key home to small guesthouses, wild horses and glorious sweeps of remote beach.

And oh boy, about those beaches. I hire a jeep and bump my way deep into the refuge, escorted by frisky chestnut mares and swooping white butterflies. Although much of the land is still off-limits (defunct bullets and bombs still exist in these parts unfortunately), the protected park reveals dozens of bays along its shores – from tiny, private smidges of sand barely big enough for my sarong and the occasional spying horse, to wide, long, wind-whipped bays strewn with pebbles, bruised coconut shells and more perving ponies.

Shops don’t exist in this protected plot of land, which leaves room for the finest of American exports: food trucks. Straddling the entrance of the island’s wildlife refuge are two island-famous snack stops, and a chef with a New York twang knocks me up the ultimate cheap beach picnic from a garish blue and white van called Sol Food. Soon, I’m sitting back on the sand and munching through spiced chicken and pineapple chutney with just the blazing sunshine and soft surf as company.

While in some parts of Puerto Rico you could dance and drink in a rum-fuelled blur until dawn, here on Vieques they get to bed early. Nightlife stretches to grabbing an after-dinner ice cream from a repurposed 1980s golf cart, or heading into ‘town’, where groups of snoozing horses wait outside pool bars for their owners.

Of course, I do find some action. At 10pm on a semi-cloudy moonlit evening, I join a glow-stick-festooned guide called Choco and drag a kayak down to Mosquito Bay, the world’s most intense, yet unheard of, bioluminescent bay. As I glide my way through the pitch black, phosphorescent dinoflagellates – that’s tiny marine plankton that glow a psychedelic blue – spark up the water with each dunk of the paddle. It’s not just surreal otherworldly sights either. Choco, my guide, may look like a burly bouncer, but his marine biology master’s degree has come in handy, and he raps – yes, raps – a series of facts to me as I float across the breezy glittering lagoon.

Back on mainland Puerto Rico it’s time to take the quiet road along the south coast. I cruise through pastel-hued, sleepy, tourist-free villages and acres of cane fields and jungle to the island’s most south-westerly point, and the simple but charming town of El Combate. It’s here that I settle in to Yaneira’s Cabins, a fairly basic, but hugely loved and inexpensive guesthouse run by local surfer Yaneira, with help from her golden labrador, Zuca.

Today I’m after her secrets. Two dazzling, talc-soft miles of them. Along the road from the cabins I collapse onto the most spectacular beach I’ve ever seen – where the sand slopes gently into a barely rippling turquoise ocean, and the beach is empty bar the occasional sunbathing dog.

I could happily spend two weeks here. The mornings pass in a tropical haze of crime books, 11am Medella beers and hours taking the same idyllic picture over and over again. Who needs to use Photoshop when it looks this good already?

families crowd around the bar, while the scent of burgers mingles with the sea air

Afternoons are spent touring the surrounding sites. There’s the Los Morrillos lighthouse, a 19th-century grey-stone building with lime-green shutters that, with its dramatic cliff-top positioning, sees the best of the island’s sunsets, every single night. Or there are the salt flats, where mounds of the white stuff sit at the side of dried-up neon-pink ponds that give the town its name – El Combate means ‘the Battle’, and locals used to fight for rights to these once-lucrative heaps of salt crystals. Even the supermarket here’s a star attraction: veg and bread supplies come with a side serving of retro fruit machines, and an ambitious queue of eager gamblers.

But no amount of lucky slot sessions can compete with a night at Annie’s Place. The open-air, beachside restaurant is crammed with fluorescent lights, sticky plastic tables, groaning fans and, well, groaning families, who huddle over towering platters of ‘medium sampler’ – that’s deep-fried goodies including cheese, mahi mahi fish and empanadas.

I try it all, then wade through a giant, $5 portion of mofongo – a hodge podge of mashed plantain, prawns and garlicky tomato sauce. Dinner-time entertainment comes in generous servings too; at the end of the room, a group of grannies kill a deafening version of Michael Jackson’s ‘Beat It’ on the karaoke. Time to turn in.

Need to know

Hix Island House

Get even more back to nature on Vieques Island with a stay at Hix Island House. The cool concrete loft-style hilltop buildings are strategically located to capture the island’s trade winds, and the rooms are fully open-air –meaning birds can fly in one door and out the other. It happens. Your kitchen is kitted out with breakfast items, so you can feast with a breezy view. From £100pn. hixislandhouse.com

El Blok

Swing by the snazzy 1950s-inspired El Blok Hotel on Vieques for cocktails and reasonably priced yet innovative local cuisine. It’s the brainchild of former music exec Simon Baeyertz, and is a very successful labour of love. elblok.com

Yaneira’s Cabins

For cheap and very cheerful rooms, try this Airbnb-listed guesthouse in south-west Puerto Rico. From £65pn. airbnb.com

If El Combate is your typical local Puerto Rican seaside town, Rincón, a two-hour drive up the country’s west coast, makes for a buzzier, more alternative beach party. This is American expat territory, a place where I’m a “dude” – and not a very cool one at that. Here I find a friendly blend of Puerto Rican-American hospitality, in a town that’s dubbed the surfing capital of the island – thanks in part to the giant waves, and also due to a namecheck in the Beach Boys’ hit ‘Surfin’ Safari’.

Around me, 60-something, sun-kissed and ludicrously ripped silver surfers cruise the pavements with hardened bare feet. Beers in one hand, surfboard in the other, their hippie attitude and washboard torsos hypnotise me, making me feel strangely carefree. And a tad frumpy.

It’s here that I meet John and Kim, a laid-back, svelte American couple who have escaped a brutal grey winter in New Jersey to spend six months catching waves in Puerto Rico. They have the right idea. “I used to skateboard down this road, Bummers Hill, in the 1970s,” John tells me, as he tears his jeep down the 20% incline slope. On either side, tree-veiled fields lead down to a mass of electric-blue ocean and frothy white waves. “It used to be just shacks at the bottom, now it’s boutique guesthouses.”

Even if development is on the up here, I have no doubt protective expats, and born-and-bred locals will keep Rincón’s alternative spirit alive. The town’s charms aren’t manufactured, and despite the more touristy vibe, it’s all very chilled.

No more so than at Villa Cofresi, a whitewashed piece of prime real-estate, with an on-the-sand location and blockbuster views. If its name sounds fancy, this unassuming two-star hotel is far from it. Local families crowd around the open-air bar, while the scent of two-dollar cheeseburgers mingles with the salty sea air. I pull up a stool and order a locally brewed Boqueron IPA and a pirata– a heady concoction of coconut water, rum, cinnamon and more rum piled into a fresh coconut.

I’m tipsy with the first sip, and rat-arsed by the second. As I gaze out to the horizon – That sky! That sand! That sea! – I realise I’ve got that lucky feeling all over again. Now where’s that pica table?

Getting There

Norwegian Air offers direct flights to San Juan, Puerto Rico, from £270 return. Book ahead for the best deals, norwegian.com