| Duluth to Smolyan | 5,208.51 mi (8,382.28 km) |
| Duluth to Sofia | 5,104.32 mi (8,214.61 km) |
| Duluth to Sopot | 5,153.04 mi (8,293.02 km) |
| Duluth to Sozopol | 5,259.20 mi (8,463.87 km) |
| Duluth to Sredets | 5,247.18 mi (8,444.52 km) |
| Duluth to Stamboliyski | 5,173.65 mi (8,326.19 km) |
| Duluth to Stara Zagora | 5,193.54 mi (8,358.20 km) |
| Duluth to Svilengrad | 5,247.13 mi (8,444.43 km) |
| Duluth to Svishtov | 5,120.46 mi (8,240.58 km) |
| Duluth to Targovishte | 5,178.98 mi (8,334.77 km) |
| Duluth to Teteven | 5,123.24 mi (8,245.06 km) |
| Duluth to Troyan | 5,139.51 mi (8,271.24 km) |
| Duluth to Tryavna | 5,165.44 mi (8,312.97 km) |
| Duluth to Tutrakan | 5,136.77 mi (8,266.84 km) |
| Duluth to Varna | 5,222.21 mi (8,404.33 km) |
