 Kostins qualified for the Latvian squad in the men's 96 kg class at the 2004 Summer Olympics in Athens by receiving a berth from the Olympic Qualifying Tournament in Tashkent, Uzbekistan.He received two straight losses and a score of two technical points in a preliminary pool match against Uzbekistan's Aleksey Cheglakov and Turkey's Mehmet Özal, who later picked up the bronze medal in the knockout stages, finishing seventeenth out of twenty-two wrestlers.In 2011, Kostins turned himself professional as a mixed martial arts fighter, and had competed in numerous global tournaments, where he claimed grand slam heavyweight titles and was ranked among 250 wrestlers under the same division.