| Helensburgh to Olivares | 1,286.81 mi (2,070.92 km) |
| Helensburgh to Olivenza | 1,202.38 mi (1,935.05 km) |
| Helensburgh to Olot | 1,008.83 mi (1,623.56 km) |
| Helensburgh to Onate | 902.92 mi (1,453.12 km) |
| Helensburgh to Onda | 1,127.73 mi (1,814.91 km) |
| Helensburgh to Onteniente | 1,203.04 mi (1,936.11 km) |
| Helensburgh to Orihuela | 1,251.20 mi (2,013.61 km) |
| Helensburgh to Osuna | 1,297.91 mi (2,088.79 km) |
| Helensburgh to Ourense | 955.47 mi (1,537.69 km) |
| Helensburgh to Oviedo | 875.87 mi (1,409.57 km) |
| Helensburgh to Paiporta | 1,163.02 mi (1,871.71 km) |
| Helensburgh to Pajara | 1,966.76 mi (3,165.20 km) |
| Helensburgh to Palafolls | 1,046.62 mi (1,684.38 km) |
| Helensburgh to Palafrugell | 1,036.31 mi (1,667.78 km) |
| Helensburgh to Palamos | 1,040.52 mi (1,674.55 km) |
