https://www.ido.com.tr/tr/ido-ege-adalari-seferleri-2026
Unfortunately it's only in Turkish but it gives very good information (sailing period, sailing schedule, ticket price) about the ferry connections between Turkey and 6 Greek islands.
These are the routes concerned:
Seferihisar – Samos (Vathy)
Kuşadası – Samos (Vathy)
Kuşadası – Samos (Pytagorion)
Kuşadası – Patmos
Bodrum Turgutreis – Leros
Fethiye – Rodos
Dikili – Mytilini (Lesvos)
Ayvalık – Mytilini (Lesvos)
Çeşme – Chios (Sakiz in Turkish)
For schedules on other routes and/or other companies on the routes mentioned above use the "Schedules" tab on this site: https://www.marmarisferry.com/en