| Merthyr Tudful to Sinop | 1,912.81 mi (3,078.37 km) |
| Merthyr Tudful to Siran | 2,155.12 mi (3,468.33 km) |
| Merthyr Tudful to Sirnak | 2,409.67 mi (3,877.99 km) |
| Merthyr Tudful to Sirvan | 2,367.80 mi (3,810.61 km) |
| Merthyr Tudful to Sivas | 2,083.43 mi (3,352.96 km) |
| Merthyr Tudful to Sivasli | 1,831.61 mi (2,947.70 km) |
| Merthyr Tudful to Siverek | 2,266.21 mi (3,647.11 km) |
| Merthyr Tudful to Sivrice | 2,235.86 mi (3,598.27 km) |
| Merthyr Tudful to Sivrihisar | 1,865.52 mi (3,002.27 km) |
| Merthyr Tudful to Sogut | 1,784.65 mi (2,872.12 km) |
| Merthyr Tudful to Sogutlu | 1,760.22 mi (2,832.80 km) |
| Merthyr Tudful to Soke | 1,773.39 mi (2,854.00 km) |
| Merthyr Tudful to Solhan | 2,287.83 mi (3,681.91 km) |
| Merthyr Tudful to Soma | 1,715.21 mi (2,760.37 km) |
| Merthyr Tudful to Sorgun | 2,003.39 mi (3,224.15 km) |
