Underwater archaeologist Franck Goddio said the city was found after a three-year expedition.
He told the paper: “The discoveries enhance the importance of the specific location of the city standing at the ‘Mouth of the Sea of the Greek’.”
He added: “We will probably have to continue working for the next 200 years for Thonis-Heracleion to be fully revealed and understood.”
As the Daily Telegraph notes, the city was the main customs transport hub into ancient Egypt.