Halkidiki or Rhodes?

Both are first-class swimming destinations, and the difference is in the kind of shore. Halkidiki has more of it: hundreds of kilometres of pale sand or small pebble across three peninsulas, often backed by pine. You can choose sunbeds and beach bars on Kassandra or rocky coves at Kavourotrypes and Karydi on Sithonia.

Rhodes concentrates its best water on the sheltered east coast, a chain of bays from Faliraki to Lindos where sand is often mixed with shingle. Tsambika is the soft-sand standout. The west coast is windier and stonier, and Prasonisi offers calm water and waves on either side of one sandbar.

Neither is a destination for serious eating. Both reward you for skipping the resort strips and heading to family tavernas. In Halkidiki the best meals are grilled fish and octopus in fishing villages such as Nikiti and Toroni, with the region's big green olives and Athos wines. Serious eaters drive to Thessaloniki for the day.

Rhodes has more distinctive island dishes to look out for, such as chickpea pitaroudia, matsi pasta and the anise spirit souma. Its meze places in the newer parts of Rhodes Town and a small upmarket tier around Lindos give a little more choice without leaving the island.

This is where the two differ most. Rhodes has one of Europe's most complete medieval fortified towns, with the Palace of the Grand Master and an archaeological museum in the old Knights' Hospital. Mosques and Byzantine churches sit inside the walls, and Lindos, Kamiros and Monte Smith lie beyond them.

Halkidiki's great monument, Mount Athos, is closed to women and permit-only for men, so most visitors see the monasteries from a boat out of Ouranoupoli. The rest, such as Olynthos, ancient Stagira and the Petralona cave, are pleasant half-days rather than reasons to come.

Rhodes offers more choice after dark. Faliraki runs until dawn for a young crowd, a lane of bars in the Old Town and the area around Mandraki keep Rhodes Town busy, and the rooftop bars of Lindos attract an older crowd.

Halkidiki's scene is mostly on Kassandra, with open-air clubs at Kallithea and bar strips in Pefkohori and Hanioti, and it is liveliest at weekends when young people drive in from Thessaloniki. In both places it is a summer-only affair, and Sithonia is for quiet tavernas.

Both are green, gentle landscapes rather than dramatic ones, and both are best for walking in spring and autumn. Halkidiki's draw is forest meeting sea, especially on Sithonia, with granite headlands, small islets and Mount Itamos. Sea kayaking, snorkelling and boat trips to the Diaporos lagoon are the main activities.

Rhodes is all about the wind. Prasonisi is one of the Mediterranean's best-known kitesurfing and windsurfing spots, and Mount Attavyros gives a real climb. The Valley of the Butterflies and Seven Springs are shady inland walks.

The outings are about equally good, but one is by road and the other by sea. From Halkidiki you drive: Thessaloniki is about an hour away for Byzantine churches and good food, with Vergina and Pella further on, and Kavala lies beyond the Athos side.

From Rhodes you take a boat to pastel Symi and the monastery of Panormitis, to quiet Halki, or across to Marmaris in Turkey for a taste of another country. The catch is that these trips depend on ferry timetables and calm summer seas.

Both have calm, shallow, sandy water and tavernas that welcome children late into the evening. Rhodes edges ahead because it offers more than the beach. A water park above Faliraki, the aquarium in Rhodes Town and the Old Town ramparts break up the week, though Lindos's stepped lanes are hard going with a pushchair.

Halkidiki's shallow sand at Gerakini, Psakoudia and on Kassandra is excellent for toddlers, and the big resorts have kids' clubs. Beyond a boat trip and the Petralona cave, though, there is little built for children, and the drives between peninsulas add effort.

Rhodes is noticeably easier without a car. The car-free Old Town, the harbour and the new town are all walkable, and buses run down the east coast to Faliraki and Lindos. Many visitors hire a car for only a few days to reach the south.

In Halkidiki, a car is essential for the whole stay. Because the peninsulas are long fingers, getting from Kassandra to Athos means driving back up one and down the next. Buses are too sparse to rely on, and southern Sithonia is close to two hours from the airport.

Neither is a shopping destination, but Rhodes gives you more to browse. Sokratous Street in the Old Town is lined with jewellery, leather and sponges, the new town has Greek high-street fashion, and Lindian-style ceramics from Archangelos make a good souvenir.

Halkidiki's resort strips sell little beyond beachwear. The best things to take home are honey, olive oil, wine, and the icons and incense sold in Ouranoupoli. For anything more, go to Thessaloniki.

Costs are much the same, and both get pricier in July and August. Halkidiki's prices are kept down by Greek and Balkan families driving in, so there are plenty of simple apartments and village rooms. The bills rise at the big Kassandra resorts and with sunbed charges on organised beaches.

On Rhodes, package hotels and all-inclusive resorts keep prices moderate on the north and east coasts. Lindos and the Old Town's boutique hotels are where you pay a premium.

Neither is a stage destination, though Halkidiki has slightly more planned. In July and August, the Kassandra Festival puts on concerts and theatre in the open-air amphitheatre at Siviri, and the Sani Festival brings jazz and classical evenings.

Rhodes's best offerings are its settings, with summer concerts in the medieval moat or the ancient stadium and a folk-dance company performing in the Old Town. Beyond that, both rely on taverna musicians.

Halkidiki is the better place to unwind. The thermal springs at Agia Paraskevi on Kassandra's southern tip offer warm mineral pools above the sea, and the coast of Sithonia and around Ouranoupoli is quiet all summer.

Rhodes has no bathing tradition, and the Kallithea rotunda is something to look at rather than bathe in. Rest there means the east-coast hotel spas or a stay in southern villages such as Lahania and Asklipio, away from the noise of the north.