| Merthyr Tudful to Ilawa | 965.50 mi (1,553.82 km) |
| Merthyr Tudful to Imielin | 986.02 mi (1,586.84 km) |
| Merthyr Tudful to Inowroclaw | 914.35 mi (1,471.51 km) |
| Merthyr Tudful to Janow Lubelski | 1,112.45 mi (1,790.31 km) |
| Merthyr Tudful to Jarocin | 888.06 mi (1,429.19 km) |
| Merthyr Tudful to Jaroslaw | 1,136.04 mi (1,828.28 km) |
| Merthyr Tudful to Jasien | 924.85 mi (1,488.40 km) |
| Merthyr Tudful to Jaslo | 1,089.73 mi (1,753.75 km) |
| Merthyr Tudful to Jastrzebie-Zdroj | 962.32 mi (1,548.71 km) |
| Merthyr Tudful to Jawor | 842.81 mi (1,356.37 km) |
| Merthyr Tudful to Jaworzno | 987.02 mi (1,588.46 km) |
| Merthyr Tudful to Jedrzejow | 1,023.71 mi (1,647.51 km) |
| Merthyr Tudful to Jelcz-Laskowice | 891.35 mi (1,434.48 km) |
| Merthyr Tudful to Jelenia Gora | 824.90 mi (1,327.55 km) |
| Merthyr Tudful to Jozefoslaw | 1,036.15 mi (1,667.53 km) |
