| Sporting Club Jacksonville | — | — | August 30, 2022 | — |
| Sporting Club Jacksonville men | USL Championship | — | August 30, 2022 | — |
| Sporting Club Jacksonville women | USL Super League | — | May 16, 2023 | — |
| Sporting Kansas City | Major League Soccer | Kansas City | 1995 | Sporting Park, Legends Field, Arrowhead Stadium |
| Springfield Demize | USL League Two | Springfield | 2006 | — |
| Springfield Storm | USL League Two | — | 2005 | — |
| St. Louis Ambush | Major Arena Soccer League | — | 2013 | Family Arena |
| St. Louis Ambush | National Professional Soccer League | — | 1991 | St. Louis Arena |
| St. Louis Busch Seniors | — | St. Louis | 1970 | — |
| St. Louis City SC | Major League Soccer | St. Louis | August 20, 2019 | Energizer Park |
| St. Louis Illusion | Major Arena Soccer League | — | 2008 | — |
| St. Louis Knights | — | St. Louis | 1994 | — |
| St. Louis Kutis S.C. | — | St. Louis | 1947 | — |
| St. Louis Lions | USL League Two | St. Louis | 2006 | — |
| St. Louis Scott Gallagher Soccer Club | — | — | 2007 | World Wide Technology Soccer Park |
| St. Louis Scullin Steel F.C. | — | St. Louis | 1918 | — |
| St. Louis Stars | National Professional Soccer League | St. Louis | 1966 | Busch Memorial Stadium |
| St. Louis Steamers | Major Indoor Soccer League | St. Louis | 1979 | St. Louis Arena |
| St. Louis Steamers | World Indoor Soccer League | — | 1998 | Enterprise Center |
| St. Louis Storm | Major Indoor Soccer League | — | July 13, 1989 | — |
| St. Petersburg FC | USL League Two | St. Petersburg | — | — |
| St. Petersburg Kickers | — | St. Petersburg | 1957 | — |
| Stade Brestois New York | — | Queensbridge | 2011 | — |
| Staten Island Vipers | A-League | Staten Island | 1998 | Tottenville High School |
| Strykers F.C. | Guam Men's Soccer League | Tamuning | — | — |
| Stumptown AC | National Independent Soccer Association | Matthews | 2018 | Sportsplex at Matthews |
| SW Florida Adrenaline | USL League Two | — | 2012 | Estero High School |
| Syracuse Suns | — | Syracuse | 1969 | — |
| Tacoma Stars | Major Arena Soccer League | — | 2003 | accesso ShoWare Center |
| Tacoma Stars | Major Indoor Soccer League | — | 1983 | — |
| Tallahassee Scorpions | Eastern Indoor Soccer League | — | 1997 | Donald L. Tucker Civic Center |
| Tallahassee Tempest | — | Tallahassee | 1998 | — |
| Tampa Bay Hawks | USL League Two | — | 2000 | — |
| Tampa Bay Rowdies | USL Championship | St. Petersburg | June 18, 2008 | George M. Steinbrenner Field, Al Lang Stadium |
| Tan Holdings FC | M*League Division 1 | — | 2008 | Ada Gym |
| Team America | North American Soccer League | Washington, D.C. | 1983 | Robert F. Kennedy Memorial Stadium |
| Team Hawaii | North American Soccer League | Honolulu | 1977 | Aloha Stadium |
| Tebo Yacht Basin F.C. | — | New York City | 1918 | — |
| Temple United FC | Texas Premier Soccer League | — | March 11, 2015 | — |
| Texas Outlaws | Major Arena Soccer League | — | 2008 | — |
| Texas Strikers | Major Arena Soccer League | — | 2012 | Ford Arena |
| The Island F.C. | MLS Next Pro | Uniondale | 2025 | — |
| Tobacco Road FC | USL League Two | — | 2013 | Durham County Stadium |
| Todd Shipyards | American Soccer League | New York City | 1921 | — |
| Toledo Slayers | USL League Two | — | 2003 | Lucas County Recreation Center |
| Toledo United FC | Great Lakes Premier League | — | 2016 | Springfield Local High School |
| Tormenta FC | USL League One | Statesboro | 2015 | Bo Pitts Field |
| Tornados de Humacao | Puerto Rico Soccer League | Humacao | 1994 | Nestor Morales Stadium |