The Dolphins have agreed to terms with veteran safety Kavon Frazier, his agency, DEC Management, announced on Twitter.
Frazier, 25, played 44 games with the Cowboys in four seasons. He made two starts.
The Cowboys made Frazier a sixth-round choice in 2016 out of Central Michigan.
He became a core special teams player, seeing action on 461 defensive snaps and 638 on special teams in his time in Dallas.
Frazier appeared in only four games last season before going on injured reserve with a pectoral injury.