All passengers who travelled on a flight from Zante to Cardiff have been instructed to self-isolate after a number tested positive for coronavirus.
Seven people from three different parties on Tuesday's 6215 Tui flight are now confirmed to have contracted Covid-19.
Public Health Wales (PHW) is now contacting the remaining passengers.
It comes after a group of teenagers from Plymouth tested positive for the virus after a holiday on the Greek island.
On Sunday, a PHW spokesperson said in a statement: "Cardiff and Vale test, trace, protect and Public Health Wales have identified at least seven confirmed cases of Covid-19 from three different parties who were infectious on Tui flight 6215 from Zante to Cardiff on 25 August.
"As a result, we are advising that all passengers on this flight are considered close contacts and must self-isolate.
"These passengers will be contacted shortly, but meanwhile, they must self-isolate at home as they may become infectious, even without developing symptoms."
They added that "anyone with symptoms should book a test without delay".