The 22-year-old prop/second rower played 21 times for the Kingstone Press League 1 outfit this year and was voted the club’s most improved player.
Igbinedion was recommended to Tigers by Oxford coach Tim Rumford, who had a previous spell on Castleford’s academy staff.
Igbinedion, a product of London Broncos’ youth system, said: “I’m really thankful to Castleford Tigers for giving me the opportunity to further my rugby career.
“It’s a fantastic opportunity for me and one that I will grab with both hands. I’m really looking forward to getting stuck in to pre-season and getting to know my new team-mates. Cas is a fantastic club with a great fan base and I can’t wait to get started.”
Tigers coach Daryl Powell said: “Daniel played at Oxford last year and trained with us for a week during the season.
“He is exceptionally strong and determined to achieve his potential as a player. I’m keen to see how he develops within our system and I’m looking forward to working with him in his first full pre-season as a full-time player.”
Castleford chief executive Steve Gill added: “Daniel spent some time this year with our first grade and really impressed us. He gives us a real underbelly at the club with some real promising youngsters now within our ranks. I’d like to thank Daniel’s agent Dave Peet for his help with this signing.”
Rumford reckons Igbinedion has the potential to play in Super League.
“Dan has worked really hard this year in a very young team and has responded well to the challenges which we set him throughout the season,” he said.
“His attitude and commitment have been great and Dan leaves Oxford with everyone’s best wishes. Dan is a good athlete, he’s surprised us with his skills at times too.
“There’s no better place for him to fulfil his potential than with Daryl and the coaching team at the Tigers.
“Castleford have a great environment which young players thrive in, it’s an exciting new challenge for Dan.
“It’s heartening to see the talent in the south of England continuing to emerge. It’s encouraging too for Oxford, as it’s a clear sign that we have a good environment ourselves and one which allows players to progress and achieve.”
Meanwhile, back-rower Andre Savelio, who ended the 2016 season on loan at Castleford, has joined Warrington Wolves from St Helens on a one-year contract.