| Holyhead to Smolyan | 1,575.66 mi (2,535.78 km) |
| Holyhead to Sofia | 1,472.24 mi (2,369.34 km) |
| Holyhead to Sopot | 1,530.29 mi (2,462.76 km) |
| Holyhead to Sozopol | 1,657.79 mi (2,667.95 km) |
| Holyhead to Sredets | 1,640.63 mi (2,640.34 km) |
| Holyhead to Stamboliyski | 1,544.46 mi (2,485.57 km) |
| Holyhead to Stara Zagora | 1,575.33 mi (2,535.24 km) |
| Holyhead to Svilengrad | 1,626.36 mi (2,617.38 km) |
| Holyhead to Svishtov | 1,513.14 mi (2,435.16 km) |
| Holyhead to Targovishte | 1,577.82 mi (2,539.26 km) |
| Holyhead to Teteven | 1,499.64 mi (2,413.44 km) |
| Holyhead to Troyan | 1,518.88 mi (2,444.40 km) |
| Holyhead to Tryavna | 1,550.68 mi (2,495.58 km) |
| Holyhead to Tutrakan | 1,546.45 mi (2,488.77 km) |
| Holyhead to Varna | 1,632.90 mi (2,627.90 km) |
