| Sintra to Orbetello | 1,106.32 mi (1,780.45 km) |
| Sintra to Oria | 1,436.69 mi (2,312.13 km) |
| Sintra to Oristano | 962.02 mi (1,548.22 km) |
| Sintra to Orta Nova | 1,333.96 mi (2,146.80 km) |
| Sintra to Orte | 1,166.00 mi (1,876.49 km) |
| Sintra to Ortona | 1,267.91 mi (2,040.51 km) |
| Sintra to Orvieto | 1,153.83 mi (1,856.90 km) |
| Sintra to Orzinuovi | 1,086.84 mi (1,749.10 km) |
| Sintra to Osimo | 1,228.93 mi (1,977.77 km) |
| Sintra to Ospitaletto | 1,096.63 mi (1,764.85 km) |
| Sintra to Ostuni | 1,433.00 mi (2,306.19 km) |
| Sintra to Ottaviano | 1,270.35 mi (2,044.43 km) |
| Sintra to Ovada | 1,011.03 mi (1,627.09 km) |
| Sintra to Ozieri | 983.74 mi (1,583.18 km) |
| Sintra to Paceco | 1,186.55 mi (1,909.56 km) |
