World Hydrography Day is celebrated on June 21 every year, since 2005. It is celebrated to raise awareness of the importance of hydrography and to publicise the work of hydrographers all around the world.

• Hydrography is the science that measures and describes the physical features of the navigable portion of the Earth’s surface and adjoining coastal areas.International Hydrographic Organization (IHO) proposed World Hydrography Day in the United Nations.
• World Hydrography Day is an opportunity for hydrographers around the globe to highlight the significance and importance of their activities. Also hydrographers based on data received suggests initiatives that support the safety of navigation, the protection of the marine environment, coastal zone management, marine spatial data infrastructures, defence and security, resource exploration, and all other components of the blue economy. 
• World Hydrography Day is observed globally on 21st June every year. The idea of the creation of World Hydrography Day belongs to the International Hydrographic Organization (IHO).
• The theme for World Hydrography Day 2023 is “Hydrography – underpinning the digital twin of the ocean”