The ferry from Mykonos to Syros is a key Cyclades connection. The crossing takes about 40 min on the fastest vessels, with tickets from €17. Every day sailings run through the season, operated by Seajets and Blue Star Ferries.
It is also one of the most rewarding short hops in the islands. Mykonos is all beach clubs, windmills and late nights in Little Venice. Syros, just to the west, is the administrative capital of the Cyclades and feels like a real Greek town that happens to have beaches: its port, Ermoupoli, is lined with neoclassical mansions, and the old Catholic quarter of Ano Syros climbs the hill above it.
Travellers use this route in two ways. Some go to Syros for a calmer, better-value stay after the intensity of Mykonos. Others use it as a stepping stone, since Ermoupoli has year-round links to Piraeus, Tinos, Paros and Naxos, which makes it a handy hub for building a loop through the central islands.
Before booking, know which Mykonos port you need: ferries use the new port at Tourlos, north of town, not the old harbour on the Chora waterfront. The conventional Blue Star ship is the cheapest way across and runs daily, while Seajets adds faster, pricier seats in the busy months. If you are bringing a vehicle, add it when you book, because summer car space goes early.