Take the fast boat to the Aegean - then slow down

It's probably Europe's cheapest roller-coaster ride and certainly one of its most exciting. You pay just €1 (67p) to board the bus from Apollonia to Vathi on the Greek island of Sifnos. And seldom has the bus conductor's traditional exhortation of "Hold tight!" been as apt as on this snaking, downhill run from the hilltop capital to the little village by the Aegean.

Unless, of course, you are eight or nine years old and prefer to let the careering bus throw you where it will, while you raise your hands above your head and scream in true theme-park style. That was the local kids' trick and the tourist children were soon picking it up. It was such a brilliant wheeze that an adult would have had to be extremely curmudgeonly to disapprove - and none of us did.

In fact, the smiles and laughter became infectious. And the best bit of all was that this hairpin-upon-hairpin ride - made hairier by a driver apparently intent on setting a record for the omnibus slalom - eventually brings you to the tranquil and beautiful bay at Vathi, where the curving sand is lined with tavernas and more tavernas.

Vathi was my base on Sifnos, one of the lesser known of the Cyclades, and a five-and-a-half-hour ferry ride from Athens-Piraeus. Island-hopping in Greece used to mean overcrowded, sweltering boats, taking forever to get anywhere - and when you did arrive, there was no telling what kind of accommodation you might find. Island-hopping today means fast, efficient ferries, equipped with drinks, edible food, games and DVDs.

And you can get a pretty good idea of what awaits you, because you've probably already explored the place on the internet. That's how my room at Xanthakis Apartments, in Vathi, was secured. The website said they were "right on the beach" - and they certainly were. Twenty-five paces took me from patio to fine sand, and 10 more steps to irresistibly swimmable sea. The Aegean Thesaurus agency not only fixed the booking here by e-mail, but also arranged ferry tickets from Piraeus to Sifnos, then to my second hop-stop, Serifos, and finally back to Piraeus.

Vathi has that edge-of-the-world feeling that all the best island beaches have. To sit there in a different taverna each night, eating excellent local dishes, beneath pin-sharp stars and a bright crescent moon, with the water lapping close to your feet, is the stuff of fantasy. It's a thoroughly charming place - a point not lost after an occasional night out in Apollonia. It is one of those towns that looks like nothing special - until you discover the one street where everything happens. When you do, you are swept up in a river of chic boutiques, rooftop restaurants, and cocktail bars that grow more lively as tonight gets closer to tomorrow.

But it's best to ration a nightlife that could rob you of your mornings, especially if, like me, you are determined to do some walking. On Sifnos, you can explore a network of footpaths with the local equivalent of an Ordnance Survey map. But I had an even better guide - printed from www.cycladen.be - with a series of outings described in full detail. One walk took me from Vathi, over rugged hills to deserted Fikiadha Bay, where the turquoise waters were perfect for swimming - if you discounted the occasional jellyfish. After that, I climbed through mountainous terrain before descending to the beach at Plati Yalos - far busier and more commercial than Vathi, but enjoyable nonetheless.

After the best part of a day walking, I took the bus back to Vathi; like all buses on the island, it arrived and left dead on time - again for the standard €1.

Green and pleasant Sifnos has a worthy, more rugged rival in Serifos - an hour north by ferry. After the tranquillity of Vathi, the seafront of Serifos's port of Livadi looked unpromisingly ordinary. Tavernas, bars, souvenir shops. It's got a long, long beach, yes, but running close behind it an equally long, busy, dusty road.

Yet familiarity breeds contentment on Serifos, largely due to Chora, the beautiful white town that spills over the island's 1,900ft summit. Chora is everything that Livadi is not. It has few of the contemporary pretensions of Apollonia on Sifnos, but it has an abundance of real charm.

To reach the heights of Chora from Livadi, you can take a meandering bus via hairpins to match those above Vathi, or you can do it on foot by taking an old stairway which does the ascent in a breathtaking straight line. Either way, from the summit of Chora you can see all of Serifos spread beneath you, as well as the surrounding islands. (Another great walk is the dramatic descent from Chora to the white beach and Caribbean-looking sea at Psili Ammos.)

Tucked away at the top of Chora is Aghios Assanasios Square - a spot so near perfect that it could be a set for the ultimate movie about a Greek island village. The neoclassical facade of the town hall is stunning, and the great blue dome atop the radiant white of St Assanasios' Church so closely matches the sky that it almost disappears into the heavens.

But the best thing is the sophisticated Stou Stratou café, its menu devoting more pages to poetry by the likes of Baudelaire than to the variety of drinks and snacks on offer. Sitting here in the noon shade with home-made chocolate cake and Puccini playing on the sound system is about as good as it gets.

GIVE ME THE FACTS

How to get there

EasyJet (0905-821 0905; www.easyjet.com) flies to Athens for around £120 return. Olympic Airlines (0870-606 0460; www.olympicairways.co.uk) flies to Athens from £200 return. Hellenic Seaways ( www.dolphins.gr) sails Piraeus-Sifnos, €18 (£13) one way; Sifnos-Serifos, €6 (£4.20) one way and Serifos-Piraeus, €17 (£12) one way.

Where to stay

Double rooms at Apartments Xanthakis (00 30 22840 71110; www.thesaurus.gr/sifnos_vathi_accommodation.htm), in Vathi, Sifnos, start at €40 (£28) a night. Villa Niki, Serifos (00 30 22810 51230; www.united-hellas.com/greece-hotels/cyclades-islands/serifos-hotels/livadi/villa-niki-rooms/index.html) offers doubles from €32 (£23) per night.

Further information

Greek National Tourism Organisation (020-7495 9300; www.gnto.co.uk). For walks go to www.cycladen.be.