Aegean Airlines and Olympic Air has launched reciprocal codeshare service, which sees both carriers codesharing on each other’s International service, covers Olympic Air’s service to Belgrade, Sofia and Tirana, as well as Aegean service to London Heathrow, Paris CDG and Rome.
The two also codeshares on each other’s Domestic service, however domestic codeshare flight is only available for reservation when connecting onto another flight.
European Codeshare Routes and flight numbers:
| Route | A3 Codeshare | OA Operating |
| Athens – Belgrade | A37391 A37393 |
OA391 OA393 |
| Belgrade – Athens | A37392 A37394 |
OA392 OA394 |
| Athens – Sofia | A37307 A37309 |
OA307 OA309 |
| Sofia – Athens | A37308 A37310 |
OA308 OA310 |
| Athens – Tirana | A37311 A37313 |
OA311 OA313 |
| Tirana – Athens | A37312 A37314 |
OA312 OA314 |
| OA Codeshare | A3 Operating | |
| Athens – London Heathrow | OA6602 OA6608 |
A3602 A3608 |
| London Heathrow – Athens | OA6603 OA6609 |
A3603 A3609 |
| Athens – Paris CDG | OA6610 OA6614 OA6618 |
A3610 A3612 A3618 |
| Paris CDG – Athens | OA6611 OA6615 OA6619 |
A3611 A3613 A3619 |
| Athens – Rome | OA6656 OA6652 OA6658 |
A3650 A3652 A3654 |
| Rome – Athens | OA6657 OA6653 OA6655 |
A3651 A3653 A3655 |
Olympic Air’s Codeshare flight number range on Domestic Aegean Airlines service is OA6000 – 6999
Aegean Airlines’ Codeshare flight number range on Domestic Olympic Air service is A37000 – 7999