Barandun came from Prec in the Canton of Graubünden . As a 15-year-old, he took part in FIS races for the first time in February 2010 . Notable successes failed to materialize in the following years, which is why he never took part in the Junior World Championships. His first appearance in the European Cup was in January 2014. It took another two years before he was able to gain a foothold in this racing series. On December 20, 2016, Barandun came second in the Super-G on the Reiteralm ; thus he achieved a podium in the European Cup for the first time in his career. Later in the season he was second twice; thus he finished fourth in the overall ranking.
Barandun made his debut in the World Cup on January 13, 2017 in the combination of Wengen . He finished in 28th place in this race and won World Cup points straight away. He achieved the best World Cup result on December 29, 2017 with 9th place in the combination of Bormio . On February 22, 2018 he won a European Cup Super G in Sarntal .
On November 4, 2018, Barandun had a fatal accident in Schluein at the age of 24 with a paraglider . When performing a spiral dive , he got too deep and hit the ground so hard that he died at the scene of the accident.