Kythnos and Milos sit at opposite ends of the western Cyclades chain, and this crossing lets you run the whole line without doubling back to Athens. Kythnos is the low-key island closest to the mainland, known for the thermal springs at Loutra and a slow, Greek-family holiday pace; Milos is the showpiece of the south-west, with the white rock of Sarakiniko, the sea caves of Kleftiko and fishing villages built into the shoreline.
The route is really two different services. From June to September last year, Seajets ran a high-speed boat from Kythnos to Milos in about 2 hr 15 min, three to six days a week depending on the month. That is the crossing most visitors want. On 12 August 2026, the day we sampled, the only departure was the Champion Jet 1 at 16:45, arriving in Adamas at 19:00, from €57.20.
For the rest of the year the options are thin and slow. In last year's data, Aegean Sea Lines sailed in winter (January, November and December) in about 4 to 4.5 hours, and Blue Star Ferries appeared once a week in every month, but on long multi-stop routings of 7 hr 35 min to almost 14 hours. Fares on those ships are low, from €9 to €18, but the timings rarely suit a holiday.
Ferryhopper has no page for this direction on its own, so the operator figures here come from the Kythnos to Milos rows of its Milos to Kythnos page, checked on 24 September 2026, plus our own timetable sample. Our older route data quoted a 1 hr 30 min crossing and €12 fares, which that source does not support, so treat the booking page as the final word for your date.
