| Boulogne-sur-Mer to Smolyan | 1,265.01 mi (2,035.83 km) |
| Boulogne-sur-Mer to Sofia | 1,162.55 mi (1,870.95 km) |
| Boulogne-sur-Mer to Sopot | 1,223.25 mi (1,968.63 km) |
| Boulogne-sur-Mer to Sozopol | 1,356.10 mi (2,182.43 km) |
| Boulogne-sur-Mer to Sredets | 1,337.60 mi (2,152.66 km) |
| Boulogne-sur-Mer to Stamboliyski | 1,235.20 mi (1,987.86 km) |
| Boulogne-sur-Mer to Stara Zagora | 1,269.34 mi (2,042.81 km) |
| Boulogne-sur-Mer to Svilengrad | 1,319.13 mi (2,122.94 km) |
| Boulogne-sur-Mer to Svishtov | 1,211.38 mi (1,949.52 km) |
| Boulogne-sur-Mer to Targovishte | 1,277.20 mi (2,055.45 km) |
| Boulogne-sur-Mer to Teteven | 1,192.61 mi (1,919.32 km) |
| Boulogne-sur-Mer to Troyan | 1,212.66 mi (1,951.58 km) |
| Boulogne-sur-Mer to Tryavna | 1,246.05 mi (2,005.32 km) |
| Boulogne-sur-Mer to Tutrakan | 1,249.72 mi (2,011.22 km) |
| Boulogne-sur-Mer to Varna | 1,335.17 mi (2,148.74 km) |
