| Greenock to Opole | 1,000.00 mi (1,609.34 km) |
| Greenock to Orzesze | 1,049.17 mi (1,688.48 km) |
| Greenock to Osowa | 918.11 mi (1,477.56 km) |
| Greenock to Ostroda | 991.09 mi (1,595.00 km) |
| Greenock to Ostroleka | 1,068.06 mi (1,718.88 km) |
| Greenock to Ostrow Mazowiecka | 1,087.78 mi (1,750.61 km) |
| Greenock to Ostrow Wielkopolski | 963.14 mi (1,550.02 km) |
| Greenock to Ostrowiec Swietokrzyski | 1,123.34 mi (1,807.83 km) |
| Greenock to Ostrzeszow | 974.96 mi (1,569.04 km) |
| Greenock to Oswiecim | 1,071.02 mi (1,723.65 km) |
| Greenock to Otwock | 1,081.97 mi (1,741.26 km) |
| Greenock to Ozarow Mazowiecki | 1,061.10 mi (1,707.67 km) |
| Greenock to Ozimek | 1,010.37 mi (1,626.04 km) |
| Greenock to Ozorkow | 1,009.83 mi (1,625.16 km) |
| Greenock to Pabianice | 1,023.20 mi (1,646.68 km) |
