Irish isles are smiling

At the Church of St Brigid and St Oliver Plunkett on the big Aran island of Inishmore, a gentle priest delivered the sermon at Easter morning mass in a soft torrent of Irish. Only a few words were recognisable, but they were the significant ones - "Boston, Massachusetts" ... "Arsenal, London" ... and even "Tokyo, Japan" - indexing the distant places where Aran Islanders have been forced to make their homes.

On the three Aran Islands, slung like a necklace across Galway Bay, emigration has long been accepted as coming with the territory - a few square miles of unyielding fields battered by widow-making, increasingly fished-out seas. As the resident population falls below 1,500, however, rapidly increasing numbers of visitors or "blow-ins" are discovering these haunting, treeless bastions of Irishness swathed in Celtic lore and littered with ancient fortresses and early Christian sites. Tourism is being seen as turning the tide of emigration; islanders take to easy trades running bike-hire shops, B&Bs and tour buses to Dun Aengus, the great clifftop fortress that is the islands' best-known attraction. In the main settlement of Kilronan, on Inishmore, where the ferries drop some 2,000 day-trippers daily in the height of the season, snack bars with names like The Ould Pier are burgeoning.

Inishmore and Inisheer are well served by their respective mainland ports, Rossaveal in Connemara and Doolin in County Clare. But three-mile-long Inishmaan, the remote "Middle Island", has always looked askance on the outside world. At the island's quay, poignantly named An Cora or "hope chest", after the luggage of those embarked on long-term travels, families were standing by their ageing tractors to await relatives as they came ashore laden with mainland booty - tins of everything from paint to Ovaltine, planks of fresh wood, rolls of roofing felt and loo paper. They disappeared in a gloriously motley convoy down the one road, a nibbled ribbon of tarmac dividing a patchwork of tiny fields hemmed by immaculate dry-limestone walls.

We passed a few beached currachs, traditional longboats with tar-covered canvas hulls, and followed a sign across the fields to Cregmore, Angela Faherty's B&B. Angela, from County Roscommon, met her Inishmaan husband in Boston and moved to the island 20 years ago. "Oh, we get a few visitors," explained Angela. "Mostly, it's anthropologists and film crews; just now there's a lot from Germany filming up at Rory Concannon's, the island's last surviving currach maker. The islanders want to keep it this way; they don't want day trippers like they get on the other islands."

As the Inishmaan community flirts with terminal collapse (just 20 children attend the island school), the people talk of developing "cultural tourism", but not with any great conviction. In the meantime, the island remains a place apart - even by Aran standards - as we discovered when we explored it the next morning. Those extraordinary walls parcel up the entire island into small fields that each sustain a single cow, and contain a sloping stone ramp the size of a double bed that feeds rainwater into the trough at its foot. In one field a woman wearing a colourful patterned shawl characteristic of the island crouched over a calf that had been born in the night, murmuring softly to it. The fields gave out at limestone terraces, freakishly flat and sea-swept clean, bar the odd perfect rectangle of rock the size of a car that some unimaginable storm had dumped there. These in turn gave way to sheer cliffs that threw up columns of spume while seals bobbed far below, their heads looking like tarred footballs.

The path led to Synge's Chair, a stone bivouac amidst a moonscape geology, where the playwright JM Synge used to come at the turn of the century to take his ease during protracted stays on the island. An old sign pointed to the house in the centre of the island where Synge produced some of his greatest works. Where an interpretation centre would have been long established on the other islands, here weeds poked from a dilapidated thatch above dirty, locked rooms housing an assortment of junk. The effect was unintentionally atmospheric, and spoke volumes for Inishmaan attitudes towards the outside world, and perhaps to the blow-in playwright himself.

In the cosy village pub, a fire was burning. Locals were lining up Easter Saturday pints of Guinness beneath decorations that had been up since Christmas (and probably not the most recent one).

A quarter-hour walk brought us through the lanes in from Faherty's B&B to the island's airport. The airport building was locked and we sat among a buzz of insects as rabbits nibbled at the runway where a sign featuring an (unlikely) airliner warned off the unwary. Then the airport came to life as plane and staff appeared all at once from different directions; a nine-seater Britten Norman Islander, the airport's fire officer, who turned out to be Angela Faherty's husband, and the elderly man who trebled as air traffic control, ticket issuer and check-in, which meant weighing passengers as well as baggage on a pair of bathroom scales. Once aboard, we skimmed low across Gregory's Sound to Inishmore, with the sea showing aquamarine beneath us; on the beach, figures were forking seaweed into trailers to be used as fertiliser on kitchen gardens.

Three minutes after take-off, we touched down at Inishmore, from where a battered Transit van ferried passengers into town. In Joe Mac's pub in Kilronan, Sean the ferry skipper joined us for a pint of Guinness. He arrived as a blow-in six years ago and was now bringing up two children on the island. Sean accepted that tourism was having its effect, but did not doubt that it would take more than a few chip shops to spoil the magic of the islands. He remembered how he had been greeted with the funniest of looks by the other skippers when he first arrived, until one of them put him right. "You trying to drown the lot of us?" the skipper asked him. "You keep turning your boat agin the sun." As Sean explained, it was considered extremely bad luck to turn the boat to the east, against the direction of the sun.

"It can get busy in the summer,' he admitted, "But the crush is very concentrated. If you avoid the middle of Kilronan and the road up to Dun Aengus, you won't see anybody." We hired bikes and, sure enough, at the other end of the island, we had all to ourselves the undisturbed ruins that litter these islands.

Like the more famous Dun Aengus further west, Dun Ducathair, the "black fort", was a great semicircular fortification perched on a clifftop above the sea and protected on the land side by upright, angled stones, or chevaux de frise. Bicycling on, we passed the old stone memorials to the sea dead that line the road around the village of Killeany, and made our way up the track to the ruins of a tiny seventh-century oratory dedicated to St Benan. The views were stunning. Inisheer appeared in the distance beyond Inishmaan, and we could see Sean's ferry leaving Kilronan for the mainland. As we watched him leave port and swing the boat round to the west, we could almost hear Aran skippers everywhere breathing a collective sigh of relief.

The best source of information on the Aran Isalnds is the Galway office of the Irish Tourist Board; call 00 353 91 563081.