Chalkias, 38, won 32 caps over a decade and was a reserve keeper in the 2004 squad that stunned the football world with a surprise European title success.
"I am proud and happy to have participated in Greece's effort to reach the quarter-finals," Chalkias, who did not feature again at the tournament after suffering an injury in Greece's second group game v 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.
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