They replace Olof Mellberg, who has gone to American St Louis City, and Andreas Engelmark.
Kristiansson comes from the club's own ranks and has previously coached the club's U19 team. Before that, he was part of Lars Lagerbäck's coaching staff for the Nigerian national team.
Landén has most recently been assistant coach at IFK Norrköping.
"We get a goal-oriented duo that works according to our model and will contribute to us taking new steps in Allsvenskan. Both have plenty of experience of coaching young players and building an environment that develops players," says BP's sports manager Philip Berglund according to the club's website.
