The Swans sign the former Greece international defender on a temporary basis as they look to relieve their injury problems at the heart of the back four
The 30 year-old-has signed a three-month deal with the Swans after he was released by Bologna over the summer, after making over 100 appearances for the Italian side and scoring four goals.
The centre back has won 15 caps for Greece and featured in their 2010 World Cup campaign in South Africa, and has previously played for AEK Athens.
He told reporters: "It's a big opportunity for me."
The Swans have been playing with only one fully fit recognised centre back in Welsh international Ashley Williams with Steven Caulker and Alan Tate out with long-term injuries, and Garry Monk playing with a foot problem.
Swans manager Brendan Rodgers had earlier commented on the Greek defender: "Until some injuries clear up, we must look at some cover.
"Moras has good experience and has played in Italy for the last four years regularly.
"He understands how we play, he is 30 years of age and I like his personality.”