In his last year as a junior, Toledo won the silver medal in the 2012 World Junior Championships in Athletics in Barcelona. He claimed the javelin title at the 2012 Ibero-American Championships in Athletics and the following month he threw an Argentine and South American junior record of 79.87 metres. He made his Olympic debut at the 2012 London Games, but did not progress beyond qualifying. He won the gold medal at the 2012 South American Under-23 Championships in Athletics with a championship record throw.