- Category: Water Feature
- Type: Island
- Latitude/Longitude: 50°10'30"N 5°37'15"W
- Eastings/Northings: 141566, 36849
- OS Grid: SW415368
- Mapcode Local: GBR DXH6.XTB
- Mapcode Global: VH052.JV9K
Location and coordinates are for the approximate centre of Porthmoina Island within this administrative area.
Geographic features and populated places may cross administrative borders.