KTEL: intercity buses, not one national app
KTEL is the usual way to move between mainland cities without a car. It is a set of regional companies, not a single Greek FlixBus clone.
How it is organised
Federation / umbrella information: ktelbus.com (POAYS). Booking is typically on the regional KTEL website or at the station. If your island or prefecture has its own portal (many do), use that.
Attica local and some port buses: ktelattikis.gr.
Athens long-distance terminals
Visitors still meet two names:
- Kifissos (Kifissou Avenue area) — historically the larger yard, Peloponnese and many long routes.
- Liosion — historically central/northern mainland directions.
OASA states that airport express X93 connects the airport with the intercity bus stations of Kifissos and Liosion (24-hour airport express family). Estimated duration ~65 minutes, traffic-dependent. Source: OASA airport express.
There has long been talk of consolidating stations (Eleonas). Treat the physical terminal on your ticket as the only truth. I am not publishing a move-in date I cannot cite from an official construction notice in this file.
Island KTEL
Crete in particular has useful intercity coaches between Chania, Rethymno and Heraklion — regional sites such as e-ktel.com (Chania–Rethymno) exist. Still: check operator for the hour you need.