Thomas won 24 caps for his country and became a firm favourite among the Dragons faithful despite previous spells at the Scarlets and Ospreys.
But persistent problems in both his knees forced Thomas, whose last international appearance came against the All Blacks in 2010, to call it a day.
And Edwards admitted Thomas will be sorely missed by the region as they gear up their preparations for the forthcoming RaboDirect PRO12 season.
"He was a fantastic all-round player who was great in the contact area and his playmaking skills were second to none." Edwards said.
"Gavin came to the region on the back of a serious injury and ended up having three terrific seasons here. That is testament to him as a competitor and a person.
"Gavin would always say to me, 'Don't look at the age on my passport, look at what I do on the pitch'.
"He was a fantastic player and servant for the Dragons. He was a man of few words in the changing room but he demonstrated to his teammates through his actions.
"He was a great influence and delivered what he said, and delivered consistently."
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