Kos

This is the planning detail that repays reading. Kos airport is 23.5 km from the main harbour in Kos Town but only 7.4 km from Mastichari and 6.6 km from Kardamena.

So if your destination is Kalymnos, flying in and going straight to Mastichari saves the entire drive into town and back out. If your destination is Rhodes or Piraeus, you have no choice: those ships use Kos Town.

Kos to Bodrum is about 20 to 30 minutes and is the most-searched route on the island by a wide margin. Boats leave from Kos Town, not from one of the smaller ports, and several operators share the crossing — Bodrum Ferryboat, EXAS and Kos Bodrum Express Lines among them.

Short as it is, this is a full international crossing out of the Schengen area. Passports, not identity cards, and border formalities at both ends that take longer than the sailing itself. There is a second, quieter crossing to Turgutreis.

From our timetable, ranked by how often they run:

• Rhodes — 15 sailings, about 2 h 40 m, on Blue Star and Dodekanisos Seaways. The island's strongest link.
• Nisyros — 4 sailings, about 50 minutes, for the volcano.
• Piraeus — 4 sailings and around 10 h 45 m to Athens.
• Samos — 3 sailings, roughly 4 hours north.

Rhodes is the terminus of the Dodecanese chain: more connections in total, but many of them run outward from it. Kos sits nearer the middle, which is why it works better if the plan is to move along the chain rather than out and back.

Kos also has the shorter run to Athens — about 10 h 45 m against roughly 12 h 50 m from Rhodes — and the shortest Turkish crossing in the region. With 15 sailings between the two islands, using both is entirely practical.

The main harbour is genuinely central: a short walk into the old town, with ticket offices, cafés, an information booth and car hire on the quayside. The central bus terminal is on Kleopatras Street, about 500–600 m away, which is where the services to Mastichari, Kardamena and Kefalos leave from.

If you are connecting between two boats at different ports, budget for that bus rather than assuming a taxi will be waiting.

Nisyros is the reason many people book a boat here at all: an active volcanic caldera you can walk into, about 50 minutes away, four sailings in our timetable. Excursion boats also run from Kardamena in season.

It is a day trip in the strict sense — go early, come back the same afternoon, and check the return time before you commit to the crater walk.

The Turkish crossings and the small-port boats to Kalymnos, Nisyros and Pserimos are warm-season services, roughly April to October, and they are the first to stop. The Blue Star ships to Rhodes and Piraeus keep running through winter because they are the island's lifeline rather than a holiday product.

May and late September give you the full network without the August queues at the Bodrum border desk, which is where the delays actually happen.