The most people blowing a chewing gum bubble simultaneously is 721 and was achieved by Ford Gum (USA) with Big League Chew® Bubble Gum at the Cal Ripken World Series in Aberdeen, Maryland, USA, on 8 August 2014.
The Cal Ripken World Series featured 18 teams, including 10 from across the USA and eight that were from other countries. The attempt happened at the opening night of the event and all of the teams participated prior to the skills competition, home run derby and first game. All of the participants used Big League Chew to blow their bubbles.
Comments below may relate to previous holders of this record.