The primary terminal for both domestic and international flights at Athens International Airport (ATH) is where Ryanair is based. I just traveled with Ryanair, and I thought Terminal 1 was really efficient and well-run. There was good signage directing travelers to the Ryanair counters, making the check-in process simple.
https://medium.com/@peterrpark....er099/a-comprehensiv

A Comprehensive Guide to Flying with Ryanair at Athens International Airport (ATH) Terminal 1 | by Jumbo Journey | Sep, 2024 | Medium

Traveling with Ryanair from Athens International Airport (ATH) can be a seamless experience when you know what to expect. Ryanair, a major low-cost airline based in Ireland, operates out of Terminal…