The short answer
If you have a spare day in Athens and want an island, these are the two real options, and they give you completely different days. Aegina is the closest of the Saronic islands and the easiest island day out in Greece, with one of the best-preserved Doric temples anywhere standing in pines on a hill. Hydra is further but not far, and it is a car-free stone town climbing in a horseshoe above its harbour, where nothing with wheels is allowed at all.
Choose Aegina for the shortest crossing, an outstanding ancient temple, and a working island rather than a resort. Choose Hydra for the town itself, a car-free day, and the better photographs. Do both if you are giving the Saronic a few days rather than an afternoon.
Aegina vs Hydra at a glance
| What you are deciding | Aegina | Hydra | Verdict |
|---|---|---|---|
| Crossing from Piraeus | The shortest of any island | Longer, but still short | Aegina |
| The set piece | The Temple of Aphaia | The stone town itself | Different pleasures |
| Traffic | Normal roads and buses | No cars, scooters or bicycles at all | Hydra is stricter |
| Getting around | Bus or car to the temple | On foot, by mule, by water taxi | Aegina, easier |
| The town | A working port town | A grey-stone amphitheatre | Hydra to look at |
| Out of season | Carries on, it is a working island | Quieter, still open | Aegina |
| Beaches | Modest | Few and small, mostly by boat | Neither |
| With children | Straightforward | Steps, no wheels, hard work | Aegina |
| Best as | A half or full day | A long day, or a night | Depends on your time |
| Ancient site | One of the best Doric temples | None | Aegina |
Full detail is in the Aegina guide and the Hydra guide.
Aegina has the better single thing to see
The Temple of Aphaia is the reason to come, and it is one of the best-preserved Doric temples anywhere. It stands in pines on a hill in the north-east with most of its columns still up and a good number still carrying their architrave, which is a rarer sight than most visitors expect.
It also forms a near-equilateral triangle with the Parthenon and the temple at Cape Sounion, which people call the holy triangle. Whether that was intended is unprovable, and it makes a good view either way.
Hydra has no ancient site. What it has is the town, and the town is the thing.
Hydra has the better single place to be
Hydra Town is a grey-stone amphitheatre: houses stacked up the slope in a horseshoe around the harbour like seats in a theatre. Because there is no second town competing for attention, the port simply is the island.
The reason it looks the way it does is the rule. Private cars, motorbikes and scooters are banned across the island, and so are bicycles. People and goods move on foot, by donkey, mule or horse, and by water taxi. That has held for decades and it is a large part of why the stone town is still intact and still looks of a piece.
It is also why Hydra is work. The town climbs steeply, luggage goes by mule or handcart, and reaching a beach usually means a boat.
Which is the better day trip
Aegina if you want ease, a real ancient site and a short crossing, and if you are travelling with children or anyone who does not want to climb. It is the easiest island day out in Greece and it is a working island with a farming interior rather than a resort, so it carries on out of season.
Hydra if you want the photographs and do not mind the steps. It is the classic Saronic day trip and most of its visitors are day-trippers.
One thing worth knowing about Hydra: it changes character after the last fast ferry leaves, when the harbour empties and the pace drops. That is the argument for staying a night rather than treating it as an afternoon. Athens to Hydra covers the crossing.
Diagram by Greece Trips. Free to reuse with credit - CC BY 4.0.
Doing both
If you have two or three days for the Saronic rather than one afternoon, both fit comfortably and they contrast well: an ancient temple and a working island on one day, a car-free stone town on the next. Saronic island hopping works through the sequencing with Poros and Spetses, and the group is in the Saronic islands.
If you are choosing one for a single day out of Athens, take Aegina when you want to see something and Hydra when you want to look at something.
Who each suits
Aegina suits families, anyone short of time, travellers who want an ancient site rather than a view, and visitors in the shoulder or winter months when a working island stays open.
Hydra suits photographers, couples, walkers, anyone who likes the idea of an island with no traffic on it, and travellers who can stay a night to see it after the boats leave.
Neither suits a beach day. Both have modest swimming and are chosen for other reasons.
Where this leaves you
Aegina is the easy one and the one with something to see: the shortest crossing from Piraeus, a superb Doric temple in the pines, and a farming island that does not shut when the season ends. Hydra is the beautiful one and the harder one: no wheels of any kind, a stone town that climbs, and a harbour that quietens the moment the day boats go. Take Aegina for a half day, Hydra for a long one.
Quick answers
Which is the easiest island day trip from Athens?
Aegina. It is the closest of the Saronic islands to Piraeus and the crossing is the shortest of any Greek island, which leaves the most time on the ground. It also has buses and normal roads, so reaching the Temple of Aphaia is straightforward.
Are cars really banned on Hydra?
Yes. Private cars, motorbikes, scooters and bicycles are all prohibited across the island. Movement is on foot, by donkey, mule or horse, or by water taxi, and the rule is enforced rather than customary. It is the reason the stone town has stayed intact.
Which has more to see, Aegina or Hydra?
Aegina, if you mean sights. The Temple of Aphaia is one of the best-preserved Doric temples anywhere and the island has a working interior beyond it. Hydra’s attraction is the town itself rather than anything in it.
Can you visit both in one trip?
Yes, and it is worth doing if you have two or three days rather than a single afternoon. They sit on the same Saronic line and the contrast between a working island with an ancient temple and a car-free stone town is the point.