Poros is served by ferry from Piraeus (Athens' port) — the journey takes about two hours on the regular ferry, or about an hour on the faster hydrofoil. Hellenic Seaways and other operators run the route. Ferries also connect Poros to the neighbouring Saronic islands of Aegina, Hydra, and Spetses, making it easy to combine islands without returning to Athens.
The tiny ferry crossing from Galatas on the Peloponnese coast takes just a few minutes and runs all day — this is the cheapest and most frequent connection if you are coming from the Peloponnese by car or bus (the nearest bus hub is Nafplio).