| SeaTac to Orbetello | 5,608.53 mi (9,026.06 km) |
| SeaTac to Oria | 5,882.13 mi (9,466.38 km) |
| SeaTac to Oristano | 5,690.50 mi (9,157.98 km) |
| SeaTac to Orta Nova | 5,786.00 mi (9,311.67 km) |
| SeaTac to Orte | 5,636.67 mi (9,071.34 km) |
| SeaTac to Ortona | 5,692.38 mi (9,161.00 km) |
| SeaTac to Orvieto | 5,614.26 mi (9,035.28 km) |
| SeaTac to Orzinuovi | 5,399.77 mi (8,690.09 km) |
| SeaTac to Osimo | 5,601.45 mi (9,014.66 km) |
| SeaTac to Ospitaletto | 5,394.02 mi (8,680.83 km) |
| SeaTac to Ostuni | 5,866.49 mi (9,441.20 km) |
| SeaTac to Ottaviano | 5,785.90 mi (9,311.50 km) |
| SeaTac to Ovada | 5,412.31 mi (8,710.26 km) |
| SeaTac to Ozieri | 5,661.44 mi (9,111.20 km) |
| SeaTac to Paceco | 5,911.65 mi (9,513.88 km) |
