Wonderful thread here -- https://community.ricksteves.com/travel-forum/greece/connecting-flights-in-athens -- helped me know what to expect arriving on one airline in Athens and leaving on a different airline.
But I have an additional question: I arrive Athens 9: 55 am and my departing flight on another airline is not till 5 pm. Since I doubt I can check in for the 5 pm flight until mid afternoon and I'll have luggage, what can I do from 11 am till say 3 pm?
Is there airport access available before checking in to my second flight?
Just trying to figure out what to do for a good 4 hours before I can check in to my next departing flight.