| Vito SIFANNO | ITA | 5 Races |
| Job SIFFELS | NED | 5 Races |
| Marton SIK | HUN | 4 Races |
| Bram SIKKENS | BEL | 3 Races |
| Damien SIKORA | FRA | 12 Races |
| Jean SIKORA | FRA | 19 Races |
| Klára SILNICOVÁ | CZE | 2 Races |
| Silo SILO | INA | 7 Races |
| Emanuel SILVA | POR | 49 Races |
| Helder SILVA | POR | 32 Races |
| Nuno SILVA | POR | 37 Races |
| Jordan SILVA | MEX | 8 Races |
| Martin SILVA | MEX | 3 Races |
| Helton SILVA | BRA | 3 Races |
| Erlon SILVA | BRA | 7 Races |