Just north of Palm Beach is the laid-back, outdoorsy Martin County, a slice of the Sunshine State without the crowds

Only 30 minutes’ drive from the mansions and skyscrapers of Palm Beach County — home, at last count, to 58 billionaires and one sitting president — is a quiet stretch of sand lined with wild grasses and seagrape bushes. Here, a sign at the low-key café in the dunes reads: “No Tipping. Service is Our Pleasure”. This is Martin County, a 22-mile stretch of barrier islands and yacht-dotted lagoons north of Palm Beach that couldn’t feel more different from its glitzy neighbour.

I came to explore it while travelling between Miami and Orlando’s Universal Studios last summer. I’d wanted to break the five-hour road trip midway (it’s a two-hour drive from each) and had been drawn to this stretch of Florida’s Atlantic coast by its similarity to the Florida Keys, 170 miles south. All fishing charters, quayside restaurants and pelicans perched on pilings, it has that laid-back charm for which Florida’s southern island chain is famous but is much closer to Orlando’s theme parks — and a lot cheaper too.

Take the free turtle nest excavation I had on Hutchinson Island, one of the barrier islands, which made me feel as if I was on an Attenborough documentary and even involved getting eggshell under my fingernails. I had the privilege of seeing not just one tiny thumb-sized loggerhead sea turtle hatch but also eight newborn leatherbacks being released into the cold Atlantic swells. Like the 20 others watching the scientist Nell Brewer at work, I couldn’t believe my luck that such an experience was entirely gratis (the county also lays on dolphin-spotting trips, beach kayaking sessions and nature walks for no charge whatsoever; discovermartin.com).

Martin County is such a well-kept secret that, everywhere I went, I was the only foreigner. Even a model friend who lives in nearby Miami and was once invited to a party at Donald Trump’s Palm Beach mansion Mar-a-Lago (and has the selfie with the president to prove it) hadn’t heard of the place, let alone visited.

He’s been missing a trick. Martin County is theplace to go if you’re trying to get yourself “shoot ready”. It’s all about embracing the outdoors, whether you’re into surfing, sailing (practically a religion, as proved by the two dozen marinas along its bays and inlets), canoeing, cycling or walking. There’s plenty of opportunity for the last of these at the Jonathan Dickinson State Park, a vast wilderness crisscrossed with paved bridleways, as well as rivers full of alligators and manatees, which visitors can spot on guided boat trips (£20pp for a 90-minute ride; jdstatepark.com).

Tiger Woods and Jack Nicklaus recently tried to build three golf courses in the park but were given short shrift. Martin County already has 28 public courses and you’ll find even more just minutes north in neighbouring St Lucie County, including the PGA Golf Club’s 54 Championship holes (18 holes from £60; pgavillage.com). Palm Beach, of course, has dozens of pay-and-play options, not to mention exclusive private members’ clubs such as the Floridian National, where Trump and Woods used to play together. Its membership is said to include Barack Obama and George W Bush, while the basketball legend Michael Jordan was allegedly asked to leave for playing music too loud on his buggy.

I’m not into golf but I did spy its fairways during a two-hour sundown sail from the city of Stuart with Treasure Coast Sailing Adventures, reclining on deck as our sleek six-man catamaran slipped along the tidal lagoon that separates Martin County from Palm Beach (£38; treasurecoastsailingadventures.com). It was too late to spot any celebs on the greens so we focused instead on finding a more benign local — the area’s resident bottlenose dolphin, which the captain Fred Newhart said he sees most days, nursing her foot-long calf. The bay is the perfect place for her to raise the youngster as the waters are teeming with shoals of fish.

Game fishing is also big business in this part of Florida and Stuart is known as the sailfish capital of the world. Quintessentially Floridian, the city is like Key West but without the spring breakers and Hemingway hordes. The 19th-century president Grover Cleveland loved it so much, he planned to build his own version of Mar-a-Lago here but died before he got the chance.

Its downtown streets are great for browsers. They’re lined with ice-cream parlours and boutiques selling everything from driftwood herons (at the Rare Earth Gallery) to barely there beachwear in crochet and macramé (at Vetu). Better still, in the courtyards behind the shops you’ll find lively restaurants and bars such as Sneaki Tiki, which serves £1.50 tacos and £2 beers (sneakitikistuart.com).

I was staying on Hutchinson Island, a 15-minute drive north of Stuart, in the nautical-themed hotel Hutchinson Shores Resort & Spa. It’s one of the pricier options in the area but does have an idyllic setting on Jensen Beach. I woke each morning to find figure-of-eight tracks on the sand beneath my balcony — signs that turtles had been nesting (room-only doubles from £242; opalcollection.com).

Other intriguing tourist sights nearby include the House of Refuge Museum, a bizarre yet fascinating Victorian home built as a haven for potential shipwreck survivors along what was then a sparsely populated coastline (£8; hsmc-fl.com/house-of-refuge). Then there’s the Elliott Museum, which has so many one-of-a-kind classic cars, they have to be lowered down on a giant jukebox-style lift for visitors to view (£16).

Two minutes from the hotel is the lagoon-side neighbourhood of Jensen Beach, home to laid-back, Keys-style hangouts such as Conchy Joe’s, with its musical bingo nights and topless mermaid mural (mains from £14; conchyjoes.com). If you like prawns, oysters and crabs, you’ll love this restaurant’s neon-lit seafood bar. As a veggie, I was more at home at nearby Tako Tiki, an open-air eating spot specialising in street tacos and burritos, where couples slow-danced between the tables and diners whooped at the scruffy hippy playing the guitar (mains from £13; takotiki.net). They were all locals but that might not be the case for long. The high-speed train that links Miami and Orlando will be stopping in Stuart from 2026. Whether the turtle-spotting will still be free once that happens is debatable. But you’ll be more than happy to pay.

Adam Edwards as a guest of America As You Like It, which has ten nights’ room-only — five in Stuart and five in Orlando — from £1,825pp, including flights and car hire (americaasyoulikeit.com)