Jones, who had been a Saints player since the age of 9, departs St Mary’s for Humberside ahead of the new season.
The Tigers will be looking to make a swift return to the Championship after their relegation from the second tier last campaign.
Jones will be hoping to help with that mission, with the versatile 22-year-old able to play in the middle of the park or at the back.
After loan spells with Scottish side St Mirren and League One Gillingham in recent seasons, the Bristol-born talent will now leave the South Coast on a permanent basis.
The player leaves with the best wishes of the club – he didn’t manage to make a Premier League appearance for Southampton.