Milos and Ios are about 36 nautical miles apart, on opposite sides of the southern Cyclades. Milos is the volcanic island of coloured cliffs and sculpted coves, with Adamas as its harbour town. Ios is the party island that also hides quiet bays and hill villages. The crossing links the western chain with the islands around Santorini, which is useful if you want to build a loop rather than retrace your steps.
There is a real choice of pace here. In the summer months Seajets runs a high-speed boat that takes about 1 hr 40 min. The rest of the traffic is on conventional ships, Fast Ferries and Blue Star Ferries, each sailing about once a week and taking three and a half to over four hours, but for a small fraction of the price.
On our 12 August 2026 sample, the two sailings summed it up: the Seajets Olympic Champion Jet left Adamas at 11:40 and reached Ios at 13:20 for €97.70, while the Fast Ferries Dionisios Solomos left at 13:10 and arrived at 16:45 for €14.50. Same afternoon on Ios, very different ticket.
Outside summer, sailings are sparse, so choose your day first. Our older route data listed Blue Star Ferries and Seajets with a 2-hour crossing; Ferryhopper's more recent figures show Fast Ferries on the route too, and longer conventional crossings, so we follow those.