| Oklahoma City FC | National Premier Soccer League | — | 2012 | Oklahoma City University |
| Oklahoma City Spirit | Lone Star Soccer Alliance | — | 1990 | — |
| Oklahoma City Warriors | — | Oklahoma City | 1986 | — |
| Oklahoma Football Club | Women's Premier Soccer League | Oklahoma | — | — |
| Omaha Flames | USL League Two | — | 1996 | Ak-Sar-Ben |
| Omaha Vipers | Major Arena Soccer League | — | 2010 | Omaha Civic Auditorium |
| One Knoxville SC | USL League One | Knoxville | 2021 | — |
| Orlando City SC | Major League Soccer | Orlando | 2013 | Inter&Co Stadium |
| Orlando City SC | USL Championship | — | 2010 | Camping World Stadium, ESPN Wide World of Sports Complex |
| Orlando City U-23 | USL League Two | Lake Mary | 1998 | Seminole Soccer Complex |
| Orlando Lions | — | Orlando | 1985 | — |
| Orlando Pride | National Women's Soccer League | Orlando | 2015 | Inter&Co Stadium |
| Orlando Sharks | — | Orlando | 2007 | Amway Arena |
| OVF Alliance | USL League Two | Houston, Albany | — | — |
| Pachuca Puerto Rico | Puerto Rico Soccer League | — | 2009 | Nestor Morales Stadium |
| Pago Youth FC | ASFA Soccer League | Pago Pago | — | Veterans Memorial Stadium |
| Paire FC | M*League Division 1 | Saipan | — | Oleai Sports Complex |
| Panathinaikos Chicago | National Premier Soccer League | Naperville | 2020 | — |
| PanSa East F.C. | ASFA Soccer League | Pago Pago | — | Veterans Memorial Stadium |
| Park City Red Wolves SC | USL League Two | Park City | — | — |
| Pawtucket Rangers | — | Pawtucket | 1913 | — |
| PDX FC | National Premier Soccer League | Portland | 2017 | — |
| Peachtree City MOBA | USL League Two | Peachtree City | 2013 | — |
| Pennsylvania Roar | Major Indoor Soccer League | — | 2013 | Sovereign Center |
| Pennsylvania Stoners | National Premier Soccer League | Allentown | 2007 | Whitehall High School |
| Pensacola Flyers | Eastern Indoor Soccer League | — | 1998 | Pensacola Civic Center |
| Philadelphia Atoms | North American Soccer League | Philadelphia | 1973 | Veterans Stadium |
| Philadelphia Atoms SC | American Soccer League | — | 2017 | — |
| Philadelphia Charge | Women's United Soccer Association | — | November 2, 2000 | Villanova Stadium |
| Philadelphia Fever | Women's Premier Soccer League Elite | — | 2012 | — |
| Philadelphia Field Club | — | Philadelphia | 1921 | — |
| Philadelphia Fury | North American Soccer League | Philadelphia | 2014 | Veterans Stadium |
| Philadelphia Fury | North American Soccer League | — | 1978 | Veterans Stadium |
| Philadelphia Independence | Women's Professional Soccer | Philadelphia | 2009 | Farrell Stadium |
| Philadelphia KiXX | Major Indoor Soccer League | — | 1995 | Liacouras Center |
| Philadelphia Lone Star FC | National Premier Soccer League | Philadelphia | 2001 | — |
| Philadelphia Nationals | — | Philadelphia | 1936 | — |
| Philadelphia Spartans | National Professional Soccer League | Philadelphia | 1967 | Temple Stadium |
| Philadelphia Union | Major League Soccer | Chester | 2008 | Subaru Park |
| Philadelphia Union Reserves | MLS Reserve League | — | 2011 | — |
| Phoenix Banat Storm | National Premier Soccer League | — | 2006 | — |
| Phoenix FC | USL Championship | Phoenix | July 2, 2012 | Sun Devil Soccer/Lacrosse Stadium |
| Phoenix Inferno | Major Indoor Soccer League | Arizona | 1980 | Arizona Veterans Memorial Coliseum |
| Phoenix Monsoon | United Premier Soccer League, National Premier Soccer League | Arizona | 2010 | — |
| Phoenix Rising FC | USL Championship | Peoria | March 13, 2014 | Phoenix Rising Soccer Stadium, Peoria Sports Complex, Casino Arizona Field, Scottsdale Stadium |
| Pittsburgh Phantoms | National Professional Soccer League | Pittsburgh | 1967 | Forbes Field |
| Pittsburgh Riverhounds SC | USL Championship | Pittsburgh | March 11, 1998 | Highmark Stadium |
| Pittsburgh Spirit | Major Indoor Soccer League | Pittsburgh | 1978 | Civic Arena |