How to get to Poros
Poros is one of the easiest Greek islands to reach, and that shapes the whole trip: you can leave Athens after breakfast and be swimming by midday. There are two completely different routes, and choosing the right one saves you time and money. The first is by sea, direct from Piraeus. The second is overland to Galatas, on the Peloponnese, and across the channel on the shuttle boat. If you are coming in a hire car, or from Nafplio, Epidaurus or Corinth, the second option is clearly better. One practical detail you will be grateful for: you do not need a car on Poros. The whole island can be covered by bus, bicycle or water taxi, and parking in Chora in August is an extreme sport.
By ferry
Two kinds of boat leave from Piraeus. The fast catamarans of Hellenic Seaways (Flying Cat and Flying Dolphin) take about an hour and ten minutes and cost between 25 and 35 euros each way. The conventional ferry run by Saronic Ferries takes around two and a half hours and drops to 15 or 18 euros, but it takes cars and has an open deck, which in summer is worth more than the speed. If you get seasick, the good news is that this is probably the gentlest route in Greece. The boat sails almost the whole way inside the Saronic Gulf, sheltered by Aegina, Agistri and the Peloponnese coast, so the swell rarely amounts to more than a soft roll. Nothing like the crossing to the Cyclades with the July meltemi. Even so, if you are sensitive, sit in the middle of the lower deck of the slow ferry and look at the horizon. In high season there are between four and six departures a day from Piraeus. In winter they drop to two or three, but the service never stops entirely. The last fast boat back to Athens usually leaves around 19:30 or 20:00, and that is the figure that really matters if you are coming on a day trip: write it down before you leave, because missing it means finding a bed at short notice in August. The other route, the one through Galatas, is the one almost nobody tells you about. Take the KTEL bus from the Kifissou terminal in Athens to Galatas (about two and a half hours, around 15 euros), and there the shuttle crosses the channel in five minutes for roughly 1.20 euros. They leave as soon as they fill, every ten or fifteen minutes. It is cheaper than the fast boat and door to door you arrive just as quickly.
By plane
Poros has no airport and does not need one. The airport to work from is Athens Eleftherios Venizelos (ATH), around two hours door to door if you combine the metro or the X96 bus to Piraeus with the fast catamaran. Reckon on about 45 minutes to the port and another hour and a quarter at sea, plus the boarding margin. If you land late, do not try to string the flight and the last boat together: sleep in Piraeus or central Athens and leave first thing. The first fast boat usually sails between 8:00 and 9:00, and arriving at Poros with the morning light on the channel makes up for the lost night.
Other options
The Poros to Galatas shuttle is the most useful transport on the island and deserves a section of its own: it crosses the 200 metres of channel in five minutes, runs from seven in the morning until midnight and costs a little over a euro. It is the door to the Peloponnese, to the lemon forest and to trips to Epidaurus, Mycenae and Nafplio. On the island itself there is a bus that leaves from the east end of Iroon square every half hour from May to October, from seven in the morning until midnight, for around 3 euros. It crosses to Kalavria, runs east to the Zoodochos Pigi monastery in about ten minutes, turns around and carries on west to Neorio in fifteen. The water taxis are the charming option: small wooden boats that take you from the port to Neorio, Russian Bay or Love Bay for a few euros, with no fixed timetable and the price agreed out loud. And for complete independence, several local outfits hire out bicycles and scooters on the road towards Kalavria for around 8 to 20 euros a day. Poros is small and fairly flat along the south coast: the bicycle genuinely works here, it is not just a nice idea.