| Boulogne-sur-Mer to Somma Lombardo | 476.93 mi (767.54 km) |
| Boulogne-sur-Mer to Somma Vesuviana | 916.67 mi (1,475.23 km) |
| Boulogne-sur-Mer to Sommacampagna | 562.55 mi (905.33 km) |
| Boulogne-sur-Mer to Sona | 560.36 mi (901.82 km) |
| Boulogne-sur-Mer to Sondrio | 491.69 mi (791.30 km) |
| Boulogne-sur-Mer to Sora | 844.49 mi (1,359.08 km) |
| Boulogne-sur-Mer to Sorbolo | 576.52 mi (927.82 km) |
| Boulogne-sur-Mer to Soresina | 534.59 mi (860.35 km) |
| Boulogne-sur-Mer to Sorisole | 505.24 mi (813.10 km) |
| Boulogne-sur-Mer to Sorrento | 928.09 mi (1,493.62 km) |
| Boulogne-sur-Mer to Sorso | 762.85 mi (1,227.68 km) |
| Boulogne-sur-Mer to Sortino | 1,146.50 mi (1,845.11 km) |
| Boulogne-sur-Mer to Soverato Marina | 1,104.98 mi (1,778.29 km) |
| Boulogne-sur-Mer to Sovicille | 684.34 mi (1,101.34 km) |
| Boulogne-sur-Mer to Spello | 745.96 mi (1,200.51 km) |
