The 23 year old was at the Skydome for five years,making 199 appearances for Paul Thompson's side.
He joined Cardiff Devils last season but after playing for Thompson in the GB team,Cowley has come back to Coventry.
Cowley told the Blaze website: "I am really excited to be back in Coventry. Cardiff was great in terms of gaining a different experience last year, the fans were great, and I made some good friends.
But to sign back for a Championship winning team is great. I know how well you are treated by the organisation in Coventry and the professionalism that the team has.
"The fans are fantastic and I made a lot of friends in the city from the previous years I spent here. It is great to be back and hopefully I can help the team win more silverware next season."