Kythnos is one of the western Cyclades, a short hop from the Attica coast, while Tinos lies on the far side of Syros in the north-east of the group. Linking them makes sense if you are working through the islands from west to east, from the thermal springs and quiet coves of Kythnos to the marble villages, dovecotes and famous pilgrimage church of Tinos, without a detour to the mainland.
Be clear about what exists, though. Ferryhopper lists Blue Star Ferries as the only company on the direct link, and in this direction its monthly data, which it says reflects last year, shows a sailing in one month only: March, once a week, taking 4 hr 35 min. Its route card gives a "from €13" figure, yet its fare table had no price for Kythnos to Tinos when we checked on 24 September 2026. The opposite direction, Tinos to Kythnos, runs once a week all year, so this is very much the weaker half of the route.
In practice, plan on two boats. The dependable way is through Athens: Kythnos has sailings to Piraeus all year, and Piraeus has Blue Star Ferries departures to Tinos every day of the year, plus Seajets high-speed boats in the warmer months. It takes most of a day, but it works on almost any date, and it lets you choose between a fast or a cheap second leg.
Whichever way you go, book the Tinos end with a little care in summer, and on the big church feast days in particular, when the island fills with pilgrims and rooms go early. Tinos Town is right on the harbour, so staying there makes arrival easy.
