Ios or Kos?

Both islands have plenty of good sand, but it comes in different shapes. Ios packs its beach life into a small space. Mylopotas is the one long, sociable bay just below Chora, Manganari in the south has sheltered coves with very clear water, and the wilder bays on the east and north coasts are reached by rough road.

Kos has more sheer length of shoreline. Long open strands run from Tigaki to Mastichari, Lambi and Psalidi sit on the edge of town, and the Kefalos peninsula has its finest bays, Paradise Beach and Agios Stefanos with its islet chapel. On both islands the meltemi roughens the north side in summer, and the south is where to go on windy days.

Neither island is a reason to travel for food, and they are much alike in what they offer: grilled fish and octopus by the harbour, and a local cheese, skotyri on Ios, wine-matured krasotyri on Kos. Kos has a little more range, with hill-village tavernas in Zia and Pyli, chickpea fritters, a market hall and small wineries near Kefalos.

On Ios the good cooking is concentrated in Chora and a few quiet bays, and in high summer much of the island eats gyros and pizza on the way out.

Kos has far more history to see. Kos Town has Roman and Hellenistic remains among its streets, the Knights' Neratzia Castle on the harbour and the Hippocrates plane tree, and the terraced Asklepieion stands on the hillside nearby. Add Old Pyli and the Antimachia castle, and that is two or three full days.

On Ios the sightseeing is Chora itself, with its windmills, chapels and lanes, plus the Early Cycladic walls at Skarkos and the legendary tomb of Homer in the north. Together they fill an afternoon or two.

Ios is the stronger party island, and its whole character in summer is built around it. The old village of Chora becomes one dense web of small bars and clubs, with crowds drifting from door to door until dawn, and Mylopotas runs beach parties from the afternoon.

Kos has a lively scene too, but it is split in two, with the bars of Kos Town's old quarter and the late clubs of Kardamena. Most of the island's resorts are quiet by midnight. That suits mixed groups, though it never matches the all-night pull of Chora.

Both are pleasant islands to be active on rather than places to travel for scenery, but the landscapes differ. Ios is bare and rocky, with old mule tracks to chapels and northern bays and boat trips to sea caves. Kos is gentler and greener in parts, with pine woods on the Dikeos range up to Mount Christos, peacocks in the Plaka forest and flamingos on the Alikes salt lake. Its flat coast also makes cycling easy, and both islands have good windsurfing.

The boat outings from each island are roughly equal in number and quality but lead to different places. From Ios you reach Santorini's caldera and Akrotiri in about an hour, Naxos's Venetian old town and the quiet cliff villages of Sikinos and Folegandros.

From Kos you can cross to Turkey for Bodrum's castle and bazaar, with a passport, climb to the volcanic crater on Nisyros or visit the sponge-diving harbour on Kalymnos. Outside high summer the Ios connections thin enough that a same-day return can fail.

Kos is much the better family island. The north-coast beaches shelve gently, resorts are built around pools and kids' clubs, there is a water park near Marmari, and flat land and cycle paths make getting about simple. Families only need to avoid Kardamena.

Ios has the shallow coves of Manganari and a quiet end of Mylopotas, but little else for children. Chora is a staircase no pushchair survives, and in July and August the party crowd sets the noise level late into the night.

Kos is the easier island to reach and to move around. It has its own airport, buses along the main road link Kos Town with the main resorts, and cycle lanes make the flat town and nearby beaches easy by bike. A hire car opens up the hill villages and the far south-west on good roads.

Ios has no airport, so every arrival is by ferry. Once there, the harbour, Chora and Mylopotas form a compact triangle served by a frequent summer bus or the old stepped path. Beyond that, the remote bays need a scooter or quad on winding roads.

Shopping is a sideline on both, but Kos offers a little more. The old quarter of Kos Town has olive oil, honey and ceramics alongside the sandals and sponges, and the Italian-era market hall sells herbs and local produce. On Ios it comes down to beachwear, jewellery and souvenirs in Chora's lanes, open late for the evening crowd.

Overall costs are much the same, but the cheap end looks different. Ios keeps its backpacker roots, with hostels, campsites, simple rooms and drinks deals in the bars, while ferry fares add to the bill. Kos is priced for package travel, with plenty of mid-range apartments and all-inclusive deals in Kardamena, Tigaki and Marmari, and cheap buses and bike hire. Both rise sharply in July and August.

Neither island has a year-round stage, but Kos has a real summer programme. The Hippokrateia festival puts concerts, theatre and dance into the Roman Odeon, the castle and the Asklepieion. On Ios there are only occasional summer events at the open-air theatre by the windmills, and on both islands saints' day festivals bring village music and dancing.

Kos is clearly better for unwinding. At Therma on the south-east coast a hot sulphur spring runs into the sea, where bathers build stone pools, and large beach resorts commonly have spas. The quiet coasts around Kefalos and the hill villages keep the pace slow.

Ios has no bathing tradition and, in peak summer, few early nights. Calm there means a boutique hotel near Manganari in June or September.