| Porsgrunn to Navodari | 1,294.13 mi (2,082.70 km) |
| Porsgrunn to Negresti-Oas | 956.02 mi (1,538.57 km) |
| Porsgrunn to Nehoiu | 1,175.12 mi (1,891.17 km) |
| Porsgrunn to Ocna Mures | 1,055.08 mi (1,697.98 km) |
| Porsgrunn to Odobesti | 1,169.53 mi (1,882.17 km) |
| Porsgrunn to Odorheiu Secuiesc | 1,093.45 mi (1,759.73 km) |
| Porsgrunn to Oltenita | 1,259.40 mi (2,026.80 km) |
| Porsgrunn to Onesti | 1,133.14 mi (1,823.61 km) |
| Porsgrunn to Oradea | 970.83 mi (1,562.40 km) |
| Porsgrunn to Orastie | 1,073.58 mi (1,727.76 km) |
| Porsgrunn to Oravita | 1,093.63 mi (1,760.03 km) |
| Porsgrunn to Orsova | 1,127.39 mi (1,814.36 km) |
| Porsgrunn to Otelu Rosu | 1,076.53 mi (1,732.50 km) |
| Porsgrunn to Otopeni | 1,217.89 mi (1,960.01 km) |
| Porsgrunn to Ovidiu | 1,295.79 mi (2,085.37 km) |
