The 21st parallel south is a circle of latitude that is 21 degrees south of the Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australasia, the Pacific Ocean and South America.

Around the world

Starting at the Prime Meridian and heading eastwards, the parallel 21° south passes through: ! scope="col" width="125" | Coordinates ! scope="col" | Country, territory or ocean ! scope="col" | Notes ! scope="row" style="background:#b0e0e6;" | Atlantic Ocean ! scope="row" | 🇳🇦 ! scope="row" | 🇧🇼 ! scope="row" | 🇿🇼 ! scope="row" | 🇲🇿 ! scope="row" style="background:#b0e0e6;" | Indian Ocean ! scope="row" | 🇲🇬 ! scope="row" style="background:#b0e0e6;" | Indian Ocean ! scope="row" | 🇫🇷 ! scope="row" style="background:#b0e0e6;" | Indian Ocean ! scope="row" | 🇦🇺 ! scope="row" style="background:#b0e0e6;" | Pacific Ocean ! scope="row" | 🇳🇨 ! scope="row" style="background:#b0e0e6;" | Pacific Ocean ! scope="row" | 🇳🇨 ! scope="row" style="background:#b0e0e6;" | Pacific Ocean ! scope="row" | 🇨🇱 ! scope="row" | 🇧🇴 ! scope="row" | 🇵🇾 ! scope="row" | 🇧🇷 ! scope="row" style="background:#b0e0e6;" | Atlantic Ocean