Lundanes competed at the 2005 Junior World Orienteering Championships in Tenero, where he won a gold medal in the long distance, a gold medal in the relay event, and placed fourth in the middle distance.[1] He received a silver and two bronze medals in the 2006 Junior World Championships.[1] In 2007 he had great success in the Junior World Championships, with victories in the long distance and the middle distance, and silver medals in both the sprint and the relay.[1]
He has 11 victories in the national junior championships.
In 2012 he won gold medal at the long distance in the World Championships in Lausanne, Switzerland.[1] He ran the last leg on the Norwegian team who achieved their third consecutive silver medal in the relay.
In Asiago in 2014, Lundanes won his first World Championship gold in middle distance.[1]Thierry Gueorgiou was first announced as the winner, but was later disqualified for undeliberatily skipping a control. At the same championships, Lundanes won a bronze medal at the long distance.[1] He became third even in the following World Championship long distance event in Inverness, Great Britain.[1]
He has 23 victories in the national championships (long 2009/2010/2011/2015/2016/2017/2018, middle 2010/2013/2017, night 2010/2012/2016, ultralong 2010/2012/2015/2016/2018, sprint 2012, relay 2009/2010/2016/2017)