Milos to Sifnos is one of the classic short hops of the western Cyclades, about 18 nautical miles of sea between two islands that pair beautifully. You trade the volcanic coastline, boat trips and moonscape rocks of Milos for Sifnos, a greener, hillier island of whitewashed villages, old footpaths and a serious food reputation.
Because the islands are so close, the choice of boat is mostly about budget and timing. The Seajets catamarans get you across in well under an hour, but the conventional ships cost a fraction of the price: Blue Star Ferries started at €6.50 when we checked, against €34.70 for Seajets. If you have a few extra hours and a flexible date, the slower ship is a bargain with open decks thrown in.
There is a good choice of sailings for most of the year. Blue Star Ferries appears in every month of last year's table, Fast Ferries and Aegean Sea Lines add sailings on some days, and in summer Seajets runs up to daily. That makes this an easy leg to fit into a western Cyclades loop of Milos, Kimolos, Sifnos and Serifos, or a stepping stone back towards Piraeus.
Two things to plan: the busy quay at Adamas in high season, where Ferryhopper suggests arriving about 45 minutes early, and transport from Kamares, the Sifnos port, to wherever you are staying. Apollonia, the capital, is about a 10-minute drive up from the harbour.