| South San Francisco to Orbetello | 6,182.51 mi (9,949.78 km) |
| South San Francisco to Oria | 6,475.08 mi (10,420.64 km) |
| South San Francisco to Oristano | 6,244.64 mi (10,049.78 km) |
| South San Francisco to Orta Nova | 6,373.93 mi (10,257.85 km) |
| South San Francisco to Orte | 6,215.27 mi (10,002.50 km) |
| South San Francisco to Ortona | 6,278.32 mi (10,103.98 km) |
| South San Francisco to Orvieto | 6,192.64 mi (9,966.08 km) |
| South San Francisco to Orzinuovi | 5,978.91 mi (9,622.13 km) |
| South San Francisco to Osimo | 6,187.39 mi (9,957.65 km) |
| South San Francisco to Ospitaletto | 5,974.19 mi (9,614.53 km) |
| South San Francisco to Ostuni | 6,459.88 mi (10,396.17 km) |
| South San Francisco to Ottaviano | 6,367.61 mi (10,247.68 km) |
| South San Francisco to Ovada | 5,984.06 mi (9,630.42 km) |
| South San Francisco to Ozieri | 6,219.88 mi (10,009.93 km) |
| South San Francisco to Paceco | 6,476.12 mi (10,422.31 km) |
