Hampshire also has previous Super League experience with Wigan Warriors and Castleford Tigers.
“I am really excited to be able to represent the club that I have followed since I was a young boy, and it has come a lot earlier than expected,” Hampshire told the Trinity website.
“It has been a long off season for me, waiting to get something sorted but my manager has managed to get the deal finalised over the last couple of days and I am looking forward to get stuck into training.”
Wakefield coach, Chris Chester added: “It has taken some work to get it over the line and I am delighted that Ryan chose to sign with us for a year.
“Ryan certainly gives us some genuine competition in the halves with Finny [Liam Finn], Milky [Jacob Miller] and also Kyle Wood.
“Really pleased; he is a fantastic young player and I’m looking forward to working with him.”