| Gourock to Smolyan | 1,650.32 mi (2,655.93 km) |
| Gourock to Sofia | 1,546.04 mi (2,488.11 km) |
| Gourock to Sopot | 1,598.89 mi (2,573.17 km) |
| Gourock to Sozopol | 1,716.87 mi (2,763.03 km) |
| Gourock to Sredets | 1,701.87 mi (2,738.90 km) |
| Gourock to Stamboliyski | 1,616.79 mi (2,601.97 km) |
| Gourock to Stara Zagora | 1,641.77 mi (2,642.18 km) |
| Gourock to Svilengrad | 1,694.41 mi (2,726.88 km) |
| Gourock to Svishtov | 1,573.81 mi (2,532.81 km) |
| Gourock to Targovishte | 1,636.18 mi (2,633.18 km) |
| Gourock to Teteven | 1,568.55 mi (2,524.34 km) |
| Gourock to Troyan | 1,586.27 mi (2,552.86 km) |
| Gourock to Tryavna | 1,615.23 mi (2,599.46 km) |
| Gourock to Tutrakan | 1,599.89 mi (2,574.77 km) |
| Gourock to Varna | 1,686.72 mi (2,714.51 km) |
