Igor Kolakovic replaced Ljubomir Travica as coach of the Serbia men's national volleyball team ahead of the 2006 FIVB World Championship, after assisting him for three years. He was the head coach of the Serbian national team from 2006 until 2014. He led Serbia to a gold medal at the 2011 European Championship and bronze at the 2007 European Championship and 2013 European Championship. In 2010 he achieved a great success at the 2010 FIVB World Championship winning a bronze medal. He helped his team win two silver medals at the 2008 FIVB World League and 2009 FIVB World League and a bronze one at the 2010 FIVB World League. In 2014 he resigned his post as a coach of Serbia after eight years. At club level, he won, among others, two titles of the Montenegrin Champion in 2007 and 2008 with Budućnost Podgorica and two titles of the Slovenian Champion in 2011 and 2012 with ACH Volley. In 2017 he was appointed as a new head coach of the Iran men's national volleyball team. He led Iran to a bronze medal of the 2017 FIVB World Grand Champions Cup defeating, among others, teams of USA, France and Italy. In 2019 Iran led by him won its 3rd Asian Champion title. In 2020 he was dismissed as the head coach of Iran.