| Siheung-si Jhikli Ambwari | India Standard Time | 03:30 |
| Siheung-si Jessup | Eastern Time | 14:00 |
| Siheung-si Jesus Maria | Peru Time | 14:00 |
| Siheung-si Jette | Central European Time | 08:00 |
| Siheung-si Jettingen-Scheppach | Central European Time | 08:00 |
| Siheung-si Jindalee | Eastern Australia Time | -01:00 |
| Siheung-si Jindivick | Eastern Australia Time | -02:00 |
| Siheung-si Jim Thorpe | Eastern Time | 14:00 |
| Siheung-si Jinan | China Time | 01:00 |
| Siheung-si Ironton | Eastern Time | 14:00 |
| Siheung-si Iruma | Japan Time | 00:00 |
| Siheung-si Ireland | United Kingdom Time | 09:00 |
| Siheung-si Ipswich | Eastern Time | 14:00 |
| Siheung-si Iowa Park | Central Time | 15:00 |
| Siheung-si Iphofen | Central European Time | 08:00 |
| Siheung-si Inzell | Central European Time | 08:00 |
| Siheung-si Inverurie | United Kingdom Time | 09:00 |
| Siheung-si Inverleigh | Eastern Australia Time | -02:00 |
| Siheung-si Innaloo | Western Australia Time | 01:00 |
| Siheung-si Intra | Central European Time | 08:00 |
| Siheung-si Ingersoll | Eastern Time | 14:00 |
| Siheung-si Ingleburn | Eastern Australia Time | -02:00 |
| Siheung-si Inez | Eastern Time | 14:00 |
| Siheung-si Inishmore | Ireland Time | 09:00 |
| Siheung-si Indapur | India Standard Time | 03:30 |
| Siheung-si Indiana | Eastern Time | 14:00 |
| Siheung-si Indialantic | Eastern Time | 14:00 |
| Siheung-si Indian Harbour Beach | Eastern Time | 14:00 |
| Siheung-si Indian Rocks Beach | Eastern Time | 14:00 |
| Siheung-si Imboden | Central Time | 15:00 |
| Siheung-si Immenstadt | Central European Time | 08:00 |
| Siheung-si Incline Village | Pacific Time | 17:00 |
| Siheung-si Inala | Eastern Australia Time | -01:00 |
| Siheung-si Inari | Eastern European Time | 07:00 |
| Siheung-si Ischgl | Central European Time | 08:00 |
| Siheung-si Irvine | Pacific Time | 17:00 |
| Siheung-si Irvine | United Kingdom Time | 09:00 |
| Siheung-si Irving | Central Time | 15:00 |
| Siheung-si Ishikawa | Japan Time | 00:00 |
| Siheung-si Issigeac | Central European Time | 08:00 |
| Siheung-si Islington | Eastern Australia Time | -02:00 |
| Siheung-si Islamorada | Eastern Time | 14:00 |
| Siheung-si Islamabad | Pakistan Time | 04:00 |
| Siheung-si Islandia | Eastern Time | 14:00 |
| Siheung-si Isle | Central Time | 15:00 |
| Siheung-si Isla Canela | Central European Time | 08:00 |
| Siheung-si Isla Mujeres | Eastern Time | 14:00 |
| Siheung-si Itabashi | Japan Time | 00:00 |
| Siheung-si Itatiaia | Brasilia Time | 12:00 |
| Siheung-si Itaunja | India Standard Time | 03:30 |