Pompey have won the race for the former Preston North End defender and are taking him to Fratton Park.
Raffery has picked Portsmouth ahead of a switch to Tranmere Rovers, a move which would have kept him in the north west.
And Portsmouth will fly Raffery to their pre-season training camp to get him up and running with his new team-mates.
The 28-year-old defender came through the youth ranks at Liverpool, but switched to Rochdale to make his senior team breakthrough.
Preston captured Rafferty in the January 2019 transfer window and he played in the Championship for the Deepdale outfit.
He made just five appearances in the league for Preston last term as he struggled for game time.
The defender will be looking to quickly get up to speed with Portsmouth and help the club’s push to win promotion up to the Championship next season.
