Sifnos to Paros links the western Cyclades with the central ones, and it is a handy crossing if you want to combine a quiet, foodie island with a bigger, better-connected one. Sifnos is known for its pottery, its walking paths between whitewashed villages and a long cooking tradition. Paros offers more of everything: beaches, nightlife in Naoussa, the old town of Parikia and ferries in every direction.
There are two very different ways to make the trip. Seajets runs high-speed boats in the warmer months that do the direct crossing in under an hour, while Blue Star Ferries sails all year on a conventional ship that takes two to three hours. The price gap is huge: Ferryhopper showed Blue Star from €4.50 and Seajets from €69.70, so the slow boat is a real bargain.
The catch is frequency. Blue Star runs only two or three days a week in Ferryhopper's data for last year, and Seajets does not sail every day in most months either. That means your dates may need to fit the boats rather than the other way round, especially outside July and August. It is also worth checking the duration of each Seajets sailing: at the start and end of the season some take over five hours because they follow a much longer routing.
Boats leave from Kamares, the harbour of Sifnos, and arrive in Parikia, the capital and main port of Paros. From Parikia you can continue almost anywhere in the Aegean, which makes this a useful stepping stone if you are heading east towards Naxos, Mykonos or Santorini.
