AIRPARK

"It's about 5 mins away from airport they give secure parking and valet our car when we come back it only needs a phone call from theairport and they pick you up. For us they check the car's battery if stored longer than 3 weeks ,and charge the battery for you also." Peter Rollett
https://airpark.gr

AIR TRAVEL PARKING

"When we are going from Athens Airport, we use this parking place. We are very pleased with them and also other friends of us are using this without any problems." Monika Nordhues

" Air Travel Parking is an off-airport private concern, who will take you to the airport in a courtesy car, and meet you on your return. Journey time around 7-8 minutes each way. Parking can be in the open or under cover (prices vary) but a really big advantage of ATP, unlike many off-airport companies is that you can take your keys with you. Online pre-booking  available, nice young entrepreneurs whose system works well". Andrew Heap
http://www.airtravelparking.gr/Index.asp

ATHENS INTERNATIONAL AIRPORT PARKING

" We parked next to the terminal last June (2016) (advance booked online and it was fine - even the numberplate recognition was ok! ) For a short trip, the one next to the terminal is easily walkable"^.(2) Jon Mines

"Athens Airport Long Term Car Park has now improved its pricing, no doubt in response to private concerns like ATP above. Online pre-booking ⁽¹⁾ will allow you to take advantage of any 'specials' available, e.g. two weeks for the price of one, Aug 2016. Downside is that can be very busy and you'll find yourself having to walk a considerable distance to the terminal, as there are no courtesy buses. " Andrew Heap
https://www.aia.gr/traveler/parking/airport-parking/Long-term-Parking

ATHENS SKYPARK

Recommended a couple of years ago, but no recent information
https://www.athensskypark.gr/en

Notes:
⁽¹⁾ Pre-booking : will give you a printable booking confirmation with instructions on how to access the car park via number plate recognition technology: - which doesn't work on some 'foreign' plates, as it cannot recognise certain letters e.g. F and R on our UK plated vehicle. If this happens, just take a ticket from the machine, and on your return stop at the intercom immediately before going down the steps from the terminal to the car park and advise your pre-booking reference number.  The staff are familiar with this problem, very helpful, and will meet you adjacent to the exit barrier, check you paperwork, and let you out.

⁽²⁾ Extra long-term parking: We're looking at leaving our car in Athens this winter, what with flight cost and availability + the improving road etc. The best quote so far is €194  for 5 months, which starts to make sense. I wonder if others travelling out of season are having the same thought?