More than 190 people were onboard the flight to Poland.
Fighter jets were scrambled on Sunday following reports of a bomb on a Ryanair flight to Greece.
Two Greek F-16s escorted a Ryanair plane from Katowice in Poland as a precaution after a bomb threat was reported on the flight, according to the Greek Defence Ministry.
The aircraft, with more than 190 people on board, landed safely at 17:40 EET at Athens International Airport.
Firefighters and police surrounded the aircraft soon after it landed at a remote part of the airport, and it was inspected by the bomb squad, the Greek news agency ANA said.
Passengers were taken off the plane and were searched, along with their luggage and the aircraft itself.
Two fighter jets intercepted the airliner belonging to the budget carrier as it entered Greek airspace above North Macedonia, the Greek Defence Ministry told AFP. It had previously been escorted by Hungarian Air Force jets.
In a statement, Ryanair told Euronews that after the crew was notified of a "potential security threat onboard" they continued to Athens "in line with safety procedures."
"Passengers disembarked normally and local authorities carried out a standard security search before clearing the aircraft to return to service," the airline said.
The origin of the bomb threat has not yet been specified.
The warning is said to have been made soon after the plane departed from Poland.