| Holyhead to Sinop | 1,976.68 mi (3,181.17 km) |
| Holyhead to Siran | 2,217.90 mi (3,569.37 km) |
| Holyhead to Sirnak | 2,473.89 mi (3,981.34 km) |
| Holyhead to Sirvan | 2,431.41 mi (3,912.98 km) |
| Holyhead to Sivas | 2,150.79 mi (3,461.37 km) |
| Holyhead to Sivasli | 1,914.71 mi (3,081.42 km) |
| Holyhead to Siverek | 2,334.90 mi (3,757.65 km) |
| Holyhead to Sivrice | 2,302.86 mi (3,706.09 km) |
| Holyhead to Sivrihisar | 1,942.90 mi (3,126.79 km) |
| Holyhead to Sogut | 1,862.85 mi (2,997.97 km) |
| Holyhead to Sogutlu | 1,835.38 mi (2,953.76 km) |
| Holyhead to Soke | 1,862.24 mi (2,996.98 km) |
| Holyhead to Solhan | 2,350.75 mi (3,783.17 km) |
| Holyhead to Soma | 1,800.21 mi (2,897.16 km) |
| Holyhead to Sorgun | 2,073.59 mi (3,337.12 km) |
