| Link | Location | |
|---|---|---|
 | Conor O'Reilly | Dublin, Ireland |
| Colm O'Shea | Galway, Ireland |
| Conor O'Sullivan | Dublin/London, Ireland |
| John O’Brien | Boston, Massachusetts, United States |
| Sagar Oak | Munich, Germany |
| Haruka Oba | Tokyo, Japan |
| Florian Obermayer | Munich, Germany |
| Chris Oberndorfer | Duvall, Washington, United States |
| DMITRIY OBREZKOV | Moscow, Russia |
 | Samuel Obuch | Brno, Czech Republic |
| Greta Obuchaviciute | Kuwait City, Kuwait |
| Katarzyna Obuchowska | Wrocław, Poland |
| Naoki Ochiai | Tokyo, Japan |
| Marcin Ochota | Wrocław, Poland |
 | Teodora Ocokoljić | BELGRADE, Serbia |
