| Watford to Idar-Oberstein | 362.99 mi (584.18 km) |
| Watford to Idstein | 390.02 mi (627.67 km) |
| Watford to Illertissen | 522.41 mi (840.74 km) |
| Watford to Illingen | 362.90 mi (584.04 km) |
| Watford to Ilmenau | 494.26 mi (795.44 km) |
| Watford to Ilsede | 451.97 mi (727.38 km) |
| Watford to Ilsenburg | 473.56 mi (762.12 km) |
| Watford to Ilsfeld | 461.31 mi (742.40 km) |
| Watford to Ilvesheim | 420.96 mi (677.46 km) |
| Watford to Immenstadt im Allgau | 551.97 mi (888.31 km) |
| Watford to Ingelheim | 386.55 mi (622.09 km) |
| Watford to Ingolstadt | 558.80 mi (899.30 km) |
| Watford to Iserlohn | 346.96 mi (558.38 km) |
| Watford to Isernhagen-Sud | 438.64 mi (705.92 km) |
| Watford to Ismaning | 585.68 mi (942.56 km) |
