| Sliven to Oignies | 1,225.12 mi (1,971.65 km) |
| Sliven to Oissel | 1,288.19 mi (2,073.15 km) |
| Sliven to Olivet | 1,234.77 mi (1,987.17 km) |
| Sliven to Ollioules | 1,034.60 mi (1,665.02 km) |
| Sliven to Olonne-sur-Mer | 1,400.09 mi (2,253.22 km) |
| Sliven to Oloron-Sainte-Marie | 1,357.23 mi (2,184.26 km) |
| Sliven to Onet Village | 1,190.78 mi (1,916.37 km) |
| Sliven to Onnaing | 1,198.05 mi (1,928.07 km) |
| Sliven to Orange | 1,081.88 mi (1,741.11 km) |
| Sliven to Orchies | 1,214.71 mi (1,954.88 km) |
| Sliven to Orleans | 1,234.75 mi (1,987.14 km) |
| Sliven to Orly | 1,222.37 mi (1,967.21 km) |
| Sliven to Ormesson-sur-Marne | 1,216.43 mi (1,957.65 km) |
| Sliven to Orsay | 1,230.97 mi (1,981.05 km) |
| Sliven to Orthez | 1,362.78 mi (2,193.19 km) |
