The meridian 129° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, Australia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole. The 129th meridian east forms a great circle with the 51st meridian west. In Australia, the meridian nominally defines the eastern border of Western Australia, and the western borders of the Northern Territory and South Australia. However, the border of Western Australia actually meets the Northern Territory border and South Australian border at the 26th parallel south, at what is known as Surveyor Generals Corner.

From Pole to Pole

Starting at the North Pole and heading south to the South Pole, the 129th meridian east passes through: ! scope="col" width="130" | Co-ordinates ! scope="col" | Country, territory or sea ! scope="col" | Notes ! scope="row" style="background:#b0e0e6;" | Arctic Ocean ! scope="row" style="background:#b0e0e6;" | Laptev Sea ! scope="row" | 🇷🇺 ! scope="row" | ! scope="row" | 🇰🇵 ! scope="row" style="background:#b0e0e6;" | Sea of Japan ! scope="row" | 🇰🇷 ! scope="row" style="background:#b0e0e6;" | East China Sea ! scope="row" | 🇯🇵 ! scope="row" style="background:#b0e0e6;" | East China Sea ! scope="row" | 🇯🇵 ! scope="row" style="background:#b0e0e6;" | East China Sea ! scope="row" | 🇯🇵 ! scope="row" style="background:#b0e0e6;" | Pacific Ocean ! scope="row" style="background:#b0e0e6;" | Halmahera Sea ! scope="row" style="background:#b0e0e6;" | Ceram Sea ! scope="row" | 🇮🇩 ! scope="row" style="background:#b0e0e6;" | Banda Sea ! scope="row" | 🇮🇩 ! scope="row" style="background:#b0e0e6;" | Timor Sea ! scope="row" | 🇦🇺 ! scope="row" style="background:#b0e0e6;" | Indian Ocean ! scope="row" style="background:#b0e0e6;" | Southern Ocean ! scope="row" | Antarctica