Porto Santo has one thing its bigger neighbour lacks - a large, empty beach.

It almost seems a shame that you can land on Porto Santo. The runway-laid middle of this tiny Portuguese isle, which floats 50km north-east of motherland Madeira, formerly nurtured a vineyard. It would have been nice to see: that such ranks of fruitful green have ever thrived here seems implausible today. Swept by Atlantic winds, Porto Santo is barren indeed: 12 km by 6 km of largely brown.

It wasn't always this way. After the island was discovered by Portuguese explorers in 1418, Porto Santo's early settlers (largely farmers and fishermen ) found native dragon trees. However, these were soon felled for their dye-producing sap. Without their wind protection - and with imported rabbits decimating crops - farming here has since been a challenge.

The island has had several admirers, though. Christopher Columbus lived here for a while;his former casa now houses the island's Columbus museum. French and Moorish pirates followed, unwelcome guests who raided the land and sent residents running into the hills.

Recent fans are the neighbouring Madeirans, who sail over for weekends, drawn by the uninterrupted 9 km-long beach that fringes Porto Santo's south side - something their own rockyshored island lacks. Madeira-born footballer Cristiano Ronaldo has reportedly invested in a soonto-open luxury hotel here.

I started my exploration on the main island of Madeira. This is part of the same volcanic chain as Porto Santo, and certainly feels topographically adventurous. Its vertical cliffs and gullies were immediately evident on the short drive from the airport into capital Funchal. There was barely enough flat space for a bowling alley, the land erupting from the sea with dramatic fervour and scant regard for coastal niceties such as promenades and beaches.

That evening, as I sat on a terrace sipping rum-and-honey ponchas, I gazed at the city lights pitching down the hillside. I rather fancied a few days of hiking in the wild interior, but my date with Madeira's sandier little sister couldn't wait.

Sailing out of Funchal at first light, I stood on the deck as the ship curled east, around the rugged Ponta de Sao Lourenco peninsula as it trailed off Madeira like a dinosaur's tail. It's not uncommon to see species such as sperm whales or bottlenose dolphins on this two-and-a-halfhour inter-island journey, but I wasn't in luck. Instead I watched as squadrons of red-blue flying fish burst out of the waves.

Approaching Porto Santo by boat, you get a good sense of the place: the way it's bookended by knobbled peaks, the highest looming in the north, and descending to a central saddle and the lovely long south-coast beach. The main "town", Vila Baleira, is the biggest hub behind the sand;otherwise there's an appealing lack of development, especially at the island's southern tip.

Soon (nothing's far in Porto Santo) I'd left the docks, passed through Vila Baleira, and was ensconced in my comfortable hotel, planning the first adventure. This came courtesy of Andre, who relished in off-roading a 4x4 around the island"s highlights.

First he drove up to Miradouro das Flores, a lookout conspicuously lacking in namesake flowers, but with fine views over to the islet of Ilheu de Baixo ou da Cal (Lime Island), where locals once excavated the dangerous cliffsides. We carried on, past the Seve Ballesteros golf course - an incongruously vibrant green - to the basalt columns of Ana Ferreira peak and the sea stack that looks like King Kong.

"Look right, " Andre instructed at a turn in the road. "There's nothing there, but it's better than what's on the left!" The desalination plant is not a must-see.

There are, in truth, few major sights on Porto Santo - though the hillier north-east, bevelled into conical peaks reaching up to 516 m, is wilder. But Andre's commentary added charm, and in just a few hours I'd had an excellent overview.

Next, I was going to investigate at a gentler pace. I hired a bicycle and pedalled down to Ponta da Calheta, the south-west tip of the island. Here, a weathered cliff and boulders smooth as bones put an abrupt end to the seemingly endless stretch of beach. Terns paddled in the rock pools, alongside a Portuguese Adonis, tensing his abs to impress his girlfriend. The whole of Porto Santo's sand strip (reputedly rich in minerals that are good for rheumatism) was uncrowded down at Calheta, where there are no resorts, just a beach bar and a ripple of dunes, it felt positively deserted.

Next day I drove up to Pico Castelo. The slopes of this 437 m peak once boasted 12 cannons, mounted in the 17th century to defend against marauding Spaniards. Now, just one heavy gun remains;fortifications have been replaced by flora.

No one else was out walking - most people come to Porto Santo for the beach. From our vantage we could look across that lovely strand, over the terracotta rooftops of Vila Baleira, and also into the rugged valleys and geological folds of the north, where streams sneaked down to tiny pebbled coves, where a little tavern offered wine-tasting. On my final evening I wandered down to the sea. Porto Santo looks prettiest at night, a twinkle of lights adrift in the Atlantic. I dug my feet into the therapeutic sand and smiled. Columbus and Cristiano might just be on to something here.