The Iranian team beat Paraguay 5-4 in the final match of Group C in Doha’s Katara beach.
Iran started the campaign with a 5-4 win over Ukraine and then defeated Senegal 3-1 on penalty shootout after two teams drew 8-8.
Iran will face either Japan or Russia in the semifinal on Tuesday.
More than 1,200 athletes from 97 countries are taking part in the games, with action split between the Katara and Al Gharafa venues between October 12 and 16.