Marinić began competing at the U23 level in 2010, finishing 9th at the U23 European Championships in Markkleeberg. In the same year he competed at the senior World Championships in Tacen and finished in 13th place, aged 19. He competed in the inaugural edition of the ICF World U23 Canoe Slalom Championships in 2012 in Wausau, Wisconsin and finished in 29th place. He competed in the same event again in 2013 in Liptovský Mikuláš, improving to 18th place.