Iran looked solid in all areas and, with players of the quality of Majid Lashgarisanami and Ahmad Eiri in their ranks, they established a two-set lead.
Iran have yet to drop a set in the tournament and they claimed the third 25-12 to secure victory.
In Pool A, Germany beat Russia 3-2 in a thrilling contest.
Russia opened up a narrow 12-11 lead in the deciding set, but in a topsy-turvy contest Germany regained the advantage with Jurgen Schrapp causing their opponents problems in defence.
And it proved decisive as they held on to take the set 15-13, prompting huge celebrations from the German fans, players and staff around the arena.
Bosnia and Herzegovina were too strong for Pool B rivals Brazil, clinching a 3-0 win.
In the women's competition, China beat Brazil 3-1 to make it two wins out of two in their Pool B contest.
China wasted one set point in the opener but made no mistake with the second, taking it 26-24, and they also wrapped up the second set 25-15.
Brazil fought back well in the next, closing it out 25-20, but China upped their game and a spike from Tan Yanhua gave them the set 25-16 and with it the match.
In Pool A, the Netherlands produced a superb all-round display to beat Host Nation Great Britain 3-0, and the USA won by the same scoreline in their Pool B match with Slovenia.