| Portsmouth Armstrong | Pacific Time | 08:00 |
| Portsmouth Arncliffe | Eastern Australia Time | -11:00 |
| Portsmouth Arnedo | Central European Time | -01:00 |
| Portsmouth Ariana | Central European Time | -01:00 |
| Portsmouth Arlesheim | Central European Time | -01:00 |
| Portsmouth Arklow | Ireland Time | 00:00 |
| Portsmouth Arkula | India Standard Time | -05:30 |
| Portsmouth Anchor Point | Alaska Time | 09:00 |
| Portsmouth Ananthapur | India Standard Time | -05:30 |
| Portsmouth Andergrove | Eastern Australia Time | -10:00 |
| Portsmouth Anderlecht | Central European Time | -01:00 |
| Portsmouth Antananarivo | East Africa Time | -03:00 |
| Portsmouth Antibes | Central European Time | -01:00 |
| Portsmouth Antigonish | Atlantic Time | 04:00 |
| Portsmouth Antwerp | Central European Time | -01:00 |
| Portsmouth Anzegem | Central European Time | -01:00 |
| Portsmouth Anzegem | Central European Time | -01:00 |
| Portsmouth Appenzell District | Central European Time | -01:00 |
| Portsmouth Apple Springs | Central Time | 06:00 |
| Portsmouth Apollo Beach | Eastern Time | 05:00 |
| Portsmouth Arden | Eastern Time | 05:00 |
| Portsmouth Applecross | Western Australia Time | -08:00 |
| Portsmouth Arcugnano | Central European Time | -01:00 |
| Portsmouth Ardross | Western Australia Time | -08:00 |
| Portsmouth Ardsley | Eastern Time | 05:00 |
| Portsmouth Åre | Central European Time | -01:00 |
| Portsmouth Argenbühl | Central European Time | -01:00 |
| Portsmouth Argent-sur-Sauldre | Central European Time | -01:00 |
| Portsmouth Aoulouz | Western European Time | 00:00 |
| Portsmouth Aougrout | Central European Time | -01:00 |
| Portsmouth Anzola dell'Emilia | Central European Time | -01:00 |
| Portsmouth Ao Nang | Indochina Time | -07:00 |
| Portsmouth Aoba Ward | Japan Time | -09:00 |
| Portsmouth Aoi Ward | Japan Time | -09:00 |
| Portsmouth Zürs | Central European Time | -01:00 |
| Portsmouth Zwingenberg | Central European Time | -01:00 |
| Portsmouth Zweisimmen | Central European Time | -01:00 |
| Portsmouth Zwiefalten | Central European Time | -01:00 |