The islands of the Saronic Gulf are so close to Athens that each summer Athenians flee there for some relief from the heat and the crowds. The summer of 2007 was the hottest in at least 90 years . . . until the summer of 2010! If these summer scorchers continue, more and more Athenians will try to escape the pulverizing heat of Athens on as many summer weekends as possible. These islands are also popular destinations for European and American travelers with limited time, who are determined not to go home without seeing at least one Greek island.

The easiest island to visit is Aegina, just 30km (17 nautical miles) from Piraeus. The main attractions—in addition to the ease of the journey—are the Doric Temple of Aphaia, one of the best-preserved Greek temples; several good beaches; and verdant pine and pistachio groves. That's the good news. The bad news is that Aegina is so close to Athens and Piraeus that it's become a bedroom suburb for Athens, with many of its 10,000 inhabitants commuting to work by boat. That said, Aegina town still has its pleasures, and the Temple of Aphaia and deserted medieval town of Paleohora are terrific. If you come here, try to avoid weekends and the month of August.

Poros is hardly an island at all; only a narrow (370m/1,214-ft.) inlet separates it from the Peloponnese. There are several decent beaches, and the landscape is wooded, gentle, and rolling, like the landscape of the adjacent mainland. Alas, Poros's pine groves were badly damaged by the summer fires of 2007, and still recovering. Poros is popular with tour groups as well as young Athenians (in part because the Naval Cadets' Training School here means that there are lots of young men eager to party). On summer nights, the waterfront is either very lively or hideously crowded, depending on your point of view.

Hydra (Idra), with its bare hills, superb natural harbor, and elegant stone mansions, is the most strikingly beautiful of the Saronic Gulf islands. One of the first Greek islands to be "discovered" by artists, writers, and bons vivants in the '50s, Hydra is not the place to experience traditional village life. The island has been declared a national monument, from which cars have been banished, but its relative quiet is increasingly being infiltrated by motorcycles. A major drawback: Few of the beaches are good for swimming, although you can swim from the rocks in and just out of Hydra town.

Spetses has always been popular with wealthy Athenians, who built—and continue to build—handsome villas. If you like wooded islands, you'll love Spetses, although summer forest fires over the last few years have destroyed some of its pine groves.

You can make a day trip to any of the islands, and some day cruises out of Piraeus rush you on and off three of them, usually with quick stops at Hydra, Poros, and Spetses. If you plan to spend the night in summer, book well in advance. The website is a useful resource for all the islands. You can access a useful website for each of the Saronic islands Cyclades by typing into your Web browser, followed by the name of the island; is a useful site for ferry schedules as is

If you go to one of these islands on a day trip, remember that, unlike the more sturdy ferries, hydrofoils cannot travel when the sea is rough. You may find yourself an overnight island visitor, grateful to be given the still-warm bed in a private home surrendered by a family member to make some money. (I speak from experience.) Greek Island Hopping, published annually by Thomas Cook, is, by its own admission, out of date by the time it sees print. Still, it's a very useful volume for finding out where (if not when) you can travel among the Greek islands.

If possible, avoid June through August, unless you have a hotel reservation and think that you'd enjoy the hustle and bustle of high season. Also, mid-July through August, boats leaving Piraeus for the islands are heavily booked—often seriously overbooked. It is sometimes possible to get a deck passage without a reservation, but even that can be difficult when as many as 100,000 Athenians leave Piraeus on a summer weekend. Most ships will not allow passengers to board without a ticket.

And remember: Some hydrofoils leave from the Piraeus Main Harbor while others leave from the Piraeus Marina Zea Harbor—and some leave from both harbors! It's a good idea to arrive early, in case your boat is leaving from a different spot from the one you expect.