Perfect pilgrimage: With few inhabitants and fewer home comforts, the tiny Welsh island of Bardsey is a testing but rewarding destination

Getting to Bardsey Island is an adventure. An email arrived with instructions to ring Colin the boatman on his mobile to check the sailing times. I got through to him immediately and the sound of crashing waves and screeching gulls came down the line. "I'm on the boat," he said. "I'll give you a ring back when I'm on dry land; the weather's a little choppy right now."

In theory, Bardsey Island should not pose too great a challenge to reach. It lies just two miles off the North Wales coast, a splodge beyond the tip of the Llyn Peninsula. But the Welsh name for the island is Ynys Enlli, "the island in the tides", and as Colin explained, there are at least eight currents in the Bardsey Sound, making crossing particularly tricky. The Bardsey Trust, which manages the island and its properties, welcomes visitors between April and October, but rules out visits in the winter. Most of the nine permanent residents leave the island during the colder months, as it is not unheard of to be cut off for six weeks at a time. Even in the spring and summer seasons you can't quite be sure of the days you'll be arriving and leaving.

Bardsey enjoys the distinction of being both near and far. In terms of adventure, it offers enormous value for money. For around £500, our family of two adults and three children could escape on a bargain-basement break. I managed to persuade my husband that for this price it was worth having a second holiday this year. Alex (12) and Cameron (seven) were easier to convince when I mentioned that this is Bear Grylls' holiday of choice, as he likes to rough it on a nearby island. Masha (four) packed her fishing net and most of her soft toys, which posed little problem, as there are no baggage restrictions on the boat.

The instructions for visiting Bardsey advise bringing enough food for the week – and a bit extra in case you have to stay longer. And it's suggested you wrap your entire luggage in bin bags to protect it from the elements on the sea crossing, as well as wearing something similar yourself, for the same reason. Colin, possibly the friendliest man in Wales, welcomed us on board, then gave us lifejackets and dragged the boat into the water with his tractor. We were off.

Measuring just one-and-a-half miles long, by half a mile wide, Bardsey is shaped like a hump-backed whale. From the mainland all that can be seen is the craggy lump of the 548ft high Mynydd Enlli mountain. But to the other side of the mount lie flatlands that have been cultivated for centuries and which now have grazing sheep and some Welsh Black cattle.

In medieval times three pilgrimages to Bardsey were equivalent to one to Rome; Christians who died on the island were guaranteed a place in heaven. Since the earliest Christian period the island attracted devout monks, and in the sixth century, St Cadfan founded a monastery here.

As our own little pilgrimage approached the island, we spied a small group waiting to help unload the boat. With so few people living here, everyone mucks in and helps. Just one narrow tractor track leads from the jetty and lighthouse at one end of the island to the Church and ruins of the medieval Abbey at the other.

The trail meanders past the boathouse, schoolroom and observatory and links the eight farmhouses in a chain; island news passes up and down this track by word of mouth. (Later on, it's how we hear about the bird talk at the observatory, and that some lobster had been caught and was now for sale.)

We were staying in Ty Nesaf ("Next House"), a pretty white-faced building that looks across to the lighthouse. In the 1870s the island's owner, Lord Newborough, started a building programme, and all but one of the farmhouses standing today date from this period. Since the Bardsey Trust took over the island in 1979, the farmhouses have been systematically repaired, but not modernised; they retain all their original features.

One concession to modern living is the bottled gas that powers the fridge, the cooker and the portable heater. But there is no bathroom and the toilet is in the Ty Bach ("little house") at the bottom of the garden. At first my boys couldn't believe their luck – no bath for a week! But I found myself filling pans with rainwater in the morning, heating them on the stove and forcing them to get clean in the scullery or garden. We emptied the toilet bucket every day into the compost box and were careful to only use the spring water for drinking. At night, we all went to bed when the sun went down, the alternative being reading books by candlelight.

Over time we discovered that there are three shops on the island, and although there's very little edible to buy, you can find felt bowls and wicker baskets and ceramic plates. All of them operate honesty boxes for payment, which makes life difficult when you haven't got any change.

Bardsey is a nature reserve. During our visit we had to be careful not to step on oystercatcher eggs near the local rock pools. We enjoyed a kitchen garden full of butterflies and bees and counted hundreds of seals lounging and moaning on the rocks.

Every night, when the darkness was at its thickest, a strange cawing and shrieking filled the air, as Manx Shearwaters flew in from the sea. Emyr the island's warden took us to see them landing on the island, waddling towards their burrows to take their place on the eggs. We waited past midnight for the crying to start and then – armed with torches – our small party watched as the birds crash-landed near their burrows, calling out to their partners that they had returned. The oldest ringed bird in the world has been caught on Bardsey, a Manx estimated to be over 55 years old.

Then, midweek, the weather turned. We had always been slightly unsure what we'd do with ourselves if the rain came in and stayed. We needn't have worried. A very under-publicised asset on Bardsey is the presence of an artist in residence. Carole Shearman lives in a converted agricultural building and keeps her door open for visitors to join her. She used to be a Steiner teacher and for the last three years has spent her summers on Bardsey giving craft classes in return for donations. (Coffee, chocolate and wine are particularly appreciated.)

By the end of the week, we still hadn't found the Bardsey apple tree, which the monks cultivated over a thousand years ago. And we hadn't had time to look for the Hermit's cave on the mountain where Merlin is said to have lived. But with the weather changed for the better, Colin advised us to be at the jetty, early next morning, prepared to depart.

On the boat I asked a woman sitting next to me if she'd visit again. "Oh, most likely," she said. "I've been coming for over 32 years." Perhaps the requisite three pilgrimages aren't quite enough.

Getting there

Bardsey is off the Llyn Peninsula in North Wales. Make your way to Porth Meudwy, near Aberdaron (08457 484950; nationalrailenquiries.co.uk). From there, charter boats ferry between the mainland and the island, costing £37 return. Alternatively, day trips are possible during the summer, leaving from Pwllheli and Porth Meudwy. These cost from £25 per adult or £60 for a family ticket (08458 113 655; enllicharter.co.uk).

Staying there

Six self-catering farmhouses are available for booking through the Bardsey Trust (08458 112233; enlli.org). Weekly rental of a house sleeping six costs from £230-£485, dependent on the season.

Alternatively, youth hostel-style accommodation is available at Cristin, the Bardsey Bird and Field Observatory. It has a generator for electricity and keeps a small shop of essential food stuffs. The cost is £145 a week for adults, including the fee for the boat, £130 for over-14s, £100 for under-13s (bbfo.org.uk).

More information

visitwales.co.uk; 08708 300 306