Amorgos sits at the far eastern edge of the Cyclades, a long, steep island of cliffs, monasteries and hiking trails, and Paros is one of the best-connected islands in the group. So the boat from Amorgos to Paros is often the first step of the journey home: from Parikia you can go on to Athens, Mykonos, Santorini or the western islands, and Paros also has an airport.
Start by checking which Amorgos port your boat leaves from. Katapola, on the south side of the island, is the main harbour and has both companies. Aegiali, in the north-west, has Blue Star sailings only, a few days a week. If you are staying in Aegiali and your ticket says Katapola, allow for the drive across the island, which takes time on the mountain road.
Speed and price pull in opposite directions on this route. Seajets runs a seasonal high-speed service from Katapola that cuts the trip to under two hours, while Blue Star Ferries sails all year on big conventional ships that call at other islands on the way, and takes three to four and a half hours. Blue Star was also the cheapest option when we checked: one adult from €11.50, against €52.70 on Seajets.
Outside summer, plan around Blue Star's timetable. In last year's data it sailed from Katapola three or four days a week in every month and from Aegiali on a similar pattern, but there was no daily boat. From November to March, pick your date first and build the rest of the trip around it.