The Colorado Comets become the first team to win both the indoor and outdoor championships, claiming their second straight outdoor crown in 1990 and the 1990-91 indoor championship in just their second year of existence.

 

SISL chronicled another historic moment by visiting the former Soviet Union.  An All-Star SISL team of indoor and outdoor standouts such as David Swissler, Jeff Reasoner, Mark Friederich, Joe Brailey and Mike Godinez played Kishinev, Moldavia in front of approximately 8,000 Soviet soccer fans in May of 1990. In November, Kishinev visited the United States on a return trip, playing the Lubbock Lazers in an indoor match.

 

The evolution continued for the Arrows (Genesis-Spurs), changing their name to North Texas United for the 1990 outdoor season.

 

The Comets swept their way through the playoffs, defeating Lubbock and the Tucson Amigos in two games. The Comets, 12-2, were then declared the champions over the Richardson Rockets, 7-7, when the championship series was canceled. 

 

Expansion continued as well, reaching into the mid-South and Southeast as the league began to blanket the Sunbelt prior to the 1990-91 indoor season, growing to a total of 18 teams. Such growth beyond the Southwest prompted the name alteration to Sunbelt Independent Soccer League prior to the 1990-91 indoor season to reflect the league's size. North Texas didn't last a year, becoming the Fort Worth Kickers for the indoor season, while Albuquerque became the New Mexico Roadrunners and the second-year El Paso franchise changed its name from Sixshooters to Spurs. 

 

Colorado swept the Oklahoma City Warriors in three games in the indoor championship series to win its third title in two years.