The 30-year-old, who had been playing with Salford, won the Challenge Cup and Super League as part of the Wigan squad in 2013.
Dudson said: “It was a no-brainer for me – the squad that has been assembled is going to be up there challenging come the end of the season and I want to be a part of that.”
Dudson becomes Catalans’ second signing for the 2021 season after the arrival of Mike McMeeken from Castleford last week.
Catalans coach Steve McNamara said: “Gil is a no-nonsense no-frills style of prop who has a big physical presence.
“His performances week to week are to a consistently high standard and he has matured into a genuine leader. We look forward to the influence he will bring to our team.”
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