| Merthyr Tudful to Sestu | 1,047.36 mi (1,685.57 km) |
| Merthyr Tudful to Settimo Torinese | 683.87 mi (1,100.58 km) |
| Merthyr Tudful to Seveso | 707.95 mi (1,139.33 km) |
| Merthyr Tudful to Sezze | 1,049.07 mi (1,688.32 km) |
| Merthyr Tudful to Siano | 1,141.69 mi (1,837.37 km) |
| Merthyr Tudful to Siena | 896.90 mi (1,443.42 km) |
| Merthyr Tudful to Signa | 865.97 mi (1,393.65 km) |
| Merthyr Tudful to Silea | 826.90 mi (1,330.76 km) |
| Merthyr Tudful to Silvi Paese | 1,034.40 mi (1,664.70 km) |
| Merthyr Tudful to Sinalunga | 916.09 mi (1,474.30 km) |
| Merthyr Tudful to Siniscola | 990.38 mi (1,593.86 km) |
| Merthyr Tudful to Sinnai | 1,050.23 mi (1,690.18 km) |
| Merthyr Tudful to Siracusa | 1,361.99 mi (2,191.91 km) |
| Merthyr Tudful to Solaro | 707.29 mi (1,138.28 km) |
| Merthyr Tudful to Soliera | 814.61 mi (1,310.98 km) |
