| São Tomé Osio Sotto | Central European Time | -02:00 |
| São Tomé Ostellato | Central European Time | -02:00 |
| São Tomé Ostermundigen | Central European Time | -02:00 |
| São Tomé Osterwasser | Central European Time | -02:00 |
| São Tomé Ossipee | Eastern Time | 04:00 |
| São Tomé Ospedaletto | Central European Time | -02:00 |
| São Tomé Osprey | Eastern Time | 04:00 |
| São Tomé Oromocto | Atlantic Time | 03:00 |
| São Tomé Orono | Central Time | 05:00 |
| São Tomé Osborne Park | Western Australia Time | -08:00 |
| São Tomé Osceola | Central Time | 05:00 |
| São Tomé Orthez | Central European Time | -02:00 |
| São Tomé Orvieto Scalo | Central European Time | -02:00 |
| São Tomé Orxeta | Central European Time | -02:00 |
| São Tomé Oberwesel | Central European Time | -02:00 |
| São Tomé Orion charter Township | Eastern Time | 04:00 |
| São Tomé Orleans | Eastern Time | 04:00 |
| São Tomé Orland | Pacific Time | 07:00 |
| São Tomé Ormond | Eastern Australia Time | -10:00 |
| São Tomé Pyrmont | Eastern Australia Time | -10:00 |
| São Tomé Pyree | Eastern Australia Time | -10:00 |
| São Tomé Qalat Sukar | Arabian Time | -03:00 |
| São Tomé Qaha | Eastern European Time | -02:00 |
| São Tomé Qala | Central European Time | -02:00 |
| São Tomé Puttaparthi | India Standard Time | -05:30 |
| São Tomé Putluru | India Standard Time | -05:30 |
| São Tomé Putnam | Eastern Time | 04:00 |
| São Tomé Putney | Eastern Australia Time | -10:00 |
| São Tomé Plainsboro Center | Eastern Time | 04:00 |
| São Tomé Placerville | Pacific Time | 07:00 |
| São Tomé Plaffeien | Central European Time | -02:00 |
| São Tomé Pittsford | Eastern Time | 04:00 |
| São Tomé Pittsboro | Eastern Time | 04:00 |
| São Tomé Pitlochry | United Kingdom Time | -01:00 |
| São Tomé Pithari | Eastern European Time | -03:00 |
| São Tomé Pismo Beach | Pacific Time | 07:00 |
| São Tomé Pireas | Eastern European Time | -03:00 |
| São Tomé Pirenópolis | Brasilia Time | 03:00 |