The meridian 99° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole.
The 99th meridian east forms a great circle with the 81st meridian west.
Starting at the North Pole and heading south to the South Pole, the 99th meridian east passes through:
| Co-ordinates | Country, territory or sea | Notes |
|---|---|---|
| Arctic Ocean | ||
| Laptev Sea | ||
| Krasnoyarsk Krai — October Revolution Island, Severnaya Zemlya | ||
| Kara Sea | ||
| Krasnoyarsk Krai Irkutsk Oblast — from Tuva Republic — from Republic of Buryatia — from | ||
| Inner Mongolia Gansu — from Qinghai — from Sichuan — from Tibet — from Sichuan — for about 9 km from Tibet — from Yunnan — for about 12 km from Tibet — for about 7 km from Yunnan — from | ||
| (Burma) | ||
| Passing through Chiang Mai at around 18°48'N | ||
| (Burma) | ||
| Strait of Malacca | Passing just west of Ko Lanta Yai island, (at) Passing just west of Ko Rawi island, (at) | |
| Island of Sumatra | ||
| Indian Ocean | Passing just east of the island of Pini, (at) | |
| Island of Siberut | ||
| Indian Ocean | ||
| Southern Ocean | ||
| Antarctica | Australian Antarctic Territory, claimed by | |