As from 20 June 2019, Athinai TMA is upgraded to Class D airspace. Therefore to enter Athinai TMA you must comply with Class D airspace entry requirements.
A pilot must contact the ATC unit on 124.025 and establish two-way radio communication prior to entering the airspace. You’ll know you’ve established two-way communication when you get a call-back that includes your callsign. During the call, you must provide ATC, with your position, altitude, current transponder code, and your destination or intentions.
Please be advised for VFR routes and altitude changes of Athinai TMA below:
If the controller is busy because of heavy traffic or any other reason, they may ask you to stay out of Class D airspace until they are ready.
Of course you can always fly up to 1000′ AGL under Athinai TMA taking into consideration the minimums above populated areas etc, in Class G airspace.