Koufonisia is the small-island antidote to Santorini. The inhabited island, Pano Koufonisi, is flat, compact and ringed by pale sand and bright turquoise water, and most visitors get around on foot or by bike. Its uninhabited twin, Kato Koufonisi, sits just across a narrow channel. Going straight from the caldera to Koufonisia swaps crowds and cliff-top views for long swims and slow evenings in a tiny harbour village.
The direct crossing is short on the map but thin on the timetable. On our sample day, 12 August 2026, Ferryhopper showed a single departure, a Seajets high-speed catamaran taking 1 hr 50 min, with fares from €99.70. That tells you what to expect in peak season: a fast, fairly expensive boat, not a choice of ships through the day. Our older route data also lists Blue Star Ferries on this route, but we could not confirm a Blue Star sailing in this direction on our sample, so treat a conventional option as something to check rather than rely on.
If the direct boat does not run on your date, or the fare is too steep, you have good fallbacks. Santorini has ferries to Naxos, Paros and Amorgos, and all three connect onward to Koufonisia. Naxos in particular works well: the leg from Naxos to Koufonisia is short and runs often in summer.
Before booking, remember that Koufonisia has limited accommodation that sells out early in July and August, and that Santorini's port, Athinios, is a busy spot under the cliffs with one road in and out. Sort your room, then your ferry, then your transfer down to the port.
