Aegean Airlines is to launch flights between Gatwick and Athens on October 28, complementing its existing service from Heathrow to the Greek capital.
The carrier has not officially announced the new route, but flights have already been loaded into Aegean's online reservation systems at aegeanair.com.
Easyjet flies between Gatwick and Athens, while BA and Aegean both offer services from Heathrow.
Aegean tried to merge with fellow Greek carrier Olympic Air in 2010 but the European Commission blocked the deal after a 10-month investigation in January 2011.
Olympic then sold its Heathrow slots to Aegean as Olympic decided to focus on the expansion of its network in south-east Europe.
aegeanair.com