| Portsmouth Hong | Central European Time | -01:00 |
| Portsmouth Hong Kong | Hong Kong Time | -08:00 |
| Portsmouth Hong Kong | Hong Kong Time | -08:00 |
| Portsmouth Hong Kong | Hong Kong Time | -08:00 |
| Portsmouth Hounslow | United Kingdom Time | 00:00 |
| Portsmouth Hotchkiss | Mountain Time | 07:00 |
| Portsmouth Hoylake | United Kingdom Time | 00:00 |
| Portsmouth Howell | Eastern Time | 05:00 |
| Portsmouth Howrah | India Standard Time | -05:30 |
| Portsmouth Hoxie | Central Time | 06:00 |
| Portsmouth Huanggang | China Time | -08:00 |
| Portsmouth Huajuapan de León | Central Time | 06:00 |
| Portsmouth Himmelkron | Central European Time | -01:00 |
| Portsmouth Hima | East Africa Time | -03:00 |
| Portsmouth Hillsborough | Eastern Time | 05:00 |
| Portsmouth Hioki | Japan Time | -09:00 |
| Portsmouth Hiram | Eastern Time | 05:00 |
| Portsmouth Hingham | Eastern Time | 05:00 |
| Portsmouth Hochdorf | Central European Time | -01:00 |
| Portsmouth Hitzacker | Central European Time | -01:00 |
| Portsmouth Homebush | Eastern Australia Time | -11:00 |
| Portsmouth Hondarribia | Central European Time | -01:00 |
| Portsmouth Homps | Central European Time | -01:00 |
| Portsmouth Holywood | United Kingdom Time | 00:00 |
| Portsmouth Holmes Beach | Eastern Time | 05:00 |
| Portsmouth Holme's Hill | United Kingdom Time | 00:00 |
| Portsmouth Hollywood | Eastern Time | 05:00 |
| Portsmouth Holly Hill | Eastern Time | 05:00 |
| Portsmouth Holly Hill | Eastern Time | 05:00 |
| Portsmouth Hokes Bluff | Central Time | 06:00 |
| Portsmouth Hokuto | Japan Time | -09:00 |
| Portsmouth Holden Hill | Central Australia Time | -10:30 |
| Portsmouth Holdenville | Central Time | 06:00 |
| Portsmouth Holdorf | Central European Time | -01:00 |
| Portsmouth Holdrege | Central Time | 06:00 |
| Portsmouth Holesov | Central European Time | -01:00 |
| Portsmouth Holgate | Eastern Australia Time | -11:00 |
| Portsmouth Hogsback | South Africa Standard Time | -02:00 |
| Portsmouth Hofheim | Central European Time | -01:00 |
| Portsmouth Hoge Hexel | Central European Time | -01:00 |
| Portsmouth Heubach | Central European Time | -01:00 |
| Portsmouth Hethersett | United Kingdom Time | 00:00 |
| Portsmouth Hewlett | Eastern Time | 05:00 |
| Portsmouth Hexham | Eastern Australia Time | -11:00 |
| Portsmouth Hexham | United Kingdom Time | 00:00 |
| Portsmouth Heydon | United Kingdom Time | 00:00 |
| Portsmouth Highgate | Western Australia Time | -08:00 |
| Portsmouth High Falls | Eastern Time | 05:00 |
| Portsmouth Higashiyama Ward | Japan Time | -09:00 |
| Portsmouth Higashi Ward | Japan Time | -09:00 |