| Helensburgh to Cascais | 1,215.68 mi (1,956.45 km) |
| Helensburgh to Castelo Branco | 1,126.38 mi (1,812.74 km) |
| Helensburgh to Castro Daire | 1,054.41 mi (1,696.91 km) |
| Helensburgh to Celorico de Basto | 1,021.69 mi (1,644.25 km) |
| Helensburgh to Chamusca | 1,164.26 mi (1,873.69 km) |
| Helensburgh to Chaves | 993.99 mi (1,599.67 km) |
| Helensburgh to Cinfaes | 1,041.98 mi (1,676.90 km) |
| Helensburgh to Coimbra | 1,104.88 mi (1,778.14 km) |
| Helensburgh to Condeixa-a-Nova | 1,111.84 mi (1,789.34 km) |
| Helensburgh to Corroios | 1,219.41 mi (1,962.45 km) |
| Helensburgh to Coruche | 1,191.50 mi (1,917.53 km) |
| Helensburgh to Costa de Caparica | 1,218.02 mi (1,960.22 km) |
| Helensburgh to Covilha | 1,094.30 mi (1,761.10 km) |
| Helensburgh to Eiras | 1,102.72 mi (1,774.66 km) |
| Helensburgh to Elvas | 1,190.13 mi (1,915.33 km) |
