Euro 2012: Greek keeper and striker announce their retirements
Chalkias, 38, won 32 caps over the period of a decade and was the reserve keeper in the 2004 Greece squad which stunned the football world with their surprise European title success in Portugal.
“I am proud and happy to have participated in Greece’s effort to reach the quarter-finals,” said Chalkias.
The keeper did not feature again at the tournament after suffering an injury in Greece’s second group game against the Czech Republic.
“This has been one of the best months of my career. Right now I am very emotional and proud – it was a dream finish for my international career,” he was quoted as saying on UEFA.com.
Liberopoulos, 36, scored 13 times for the national team and his 76th and last appearance came as a second-half substitute in the 4-2 quarter-final defeat by Germany on Friday.
“I feel blessed that I get to close this chapter among a team that are like family to me,” he said.
Liberopoulos made his international debut in 1996 and was called up on a regular basis after that but was left out of the squad for the 2004 triumph when the Greeks beat hosts Portugal in the final.
He added: “It’s a big honour for me. At the end of the match, I felt that I didn’t want to leave the pitch. Now I will continue supporting this team as a fan.”