The 27-year-old came through the Black and Whites’ academy and has made 148 appearances in Super League.
“I’m really excited to be joining Cas next year, especially with the appointment of Ryan Carr,” he told the club website., external
“The club have made some great signings for next year and I can’t wait to get down and see what we can achieve as a collective.”
Hull FC head coach John Cartwright said he was disappointed to not be able to keep Lane at the club.
A broken arm has restricted the player, who made his debut for the Super League side in 2018, to 10 league appearances this season.
“He’s a player we’d have liked to have kept, there’s no doubt about that,” he told BBC Radio Humberside.
“He’s been mulling it over for a while… he got a really good offer from Cas and at the end of the day nobody is going to hold it against him.
“We’re very happy for him that he’s sorted his future out but I love Jordan as a footballer, he’s a good team man.
He added: “Unfortunately he’s been injured for a chunk of the season but when he’s on the field he’s no frills and he brings leadership.
“He’s very popular amongst his peers and an all-round good guy.
