World Hydrography Day2026 · Date · History · Messages
The International Hydrographic Organization states that World Hydrography Day is celebrated on 21 June; its 2026 page confirms 21 June 2026.
About World Hydrography Day
World Hydrography Day is observed each year on 21 June under the International Hydrographic Organization. It highlights hydrography—the measurement and description of seas, oceans, coastal areas, lakes and waterways—and the role of reliable marine data in safe navigation and wider ocean knowledge.
The institutional history is unusually clear. The IHO adopted the observance, the United Nations General Assembly welcomed that adoption in resolution A/RES/60/30 on 29 November 2005, and IHO planning documents identify 2006 as the first year of celebrations.
Why World Hydrography Day matters
The day gives hydrographic offices, technical organizations and maritime communities an opportunity to explain how surveying, charting and ocean data support navigation, marine planning, environmental protection and disaster resilience.
Annual themes change. They should be treated as edition-specific campaign material rather than permanent definitions of the observance.
History of World Hydrography Day
IHO records show that work toward an internationally recognized hydrography day took place over several years before 2005.
On 29 November 2005, the UN General Assembly adopted resolution A/RES/60/30, welcoming the IHO’s adoption of World Hydrography Day as an annual 21 June observance and urging cooperation with the organization to promote safe navigation.
IHO Circular Letter 08/2006 set out plans for the first year of celebrations in 2006. IHO historical material explains that 21 June was chosen as the date associated with creation of the International Hydrographic Bureau, the organization’s predecessor structure, in 1921.
How the observance developed
This timeline uses documented milestones from reviewed sources. Missing stages are left out rather than guessed.
International Hydrographic Organization (IHO)
The UN resolution and IHO records explicitly refer to adoption of World Hydrography Day by the IHO.
International Hydrographic Organization (IHO)
IHO adopted World Hydrography Day as an annual 21 June observance before UN General Assembly recognition in November 2005.
First documented observance
IHO Circular Letter 08/2006 describes 2006 as the first year of World Hydrography Day celebrations and directs celebration on 21 June.
Welcomed the IHO’s adoption of World Hydrography Day as an annual 21 June observance and urged States to work with the IHO to promote safe navigation.
United Nations General Assembly · Resolution A/RES/60/30
International Hydrographic Organization Secretariat
The IHO maintains the annual World Hydrography Day programme, theme and Member State participation material.
What the evidence establishes
Confirmed institutional roles and milestones are shown first. Details that could not be established from the reviewed sources are listed separately below.
4 fields not established in reviewed sources
Later institutional actions
Later recognition, renaming, mergers or date changes are kept separate from original establishment.
How to Observe World Hydrography Day
Learn how nautical charts, bathymetric surveys and hydrographic data are produced and updated.
Explore the work of your national hydrographic office or another authoritative maritime mapping organization.
Use the day to discuss how accurate marine data supports navigation, ports, coastal management, science and environmental protection.
Check the IHO’s current-year theme and participation material before using a campaign slogan, because the theme changes by edition.
World Hydrography Day Facts
World Hydrography Day is observed annually on 21 June.
The International Hydrographic Organization adopted the observance.
UN General Assembly resolution A/RES/60/30 of 29 November 2005 welcomed the IHO’s adoption of the day.
IHO planning material identifies 2006 as the first year of World Hydrography Day celebrations.
IHO historical material links 21 June to the creation of the International Hydrographic Bureau in 1921.
World Hydrography Day Messages
Happy World Hydrography Day—recognition to the people who turn careful measurements into safer navigation and better knowledge of our waters.
On World Hydrography Day, thank you to hydrographers and marine-data professionals whose work helps make coasts, ports and oceans better understood.
Wishing the hydrographic community a meaningful World Hydrography Day and continued success in improving the quality and reach of marine information.
May World Hydrography Day encourage greater appreciation for the surveys, charts and data that support safe and responsible use of the seas.
Happy World Hydrography Day—here’s to accurate data, international cooperation and a clearer picture of the world beneath the waterline.
Topic and context
What this page does not assume
- Keep the source-defined country, community, organizer or institutional scope; do not silently broaden it.
- Do not treat the title alone as proof of government recognition or public-holiday status.
- Do not add a creator, founding story or origin claim unless the supporting evidence establishes it.
Evidence & sources
Sources used across the guide are gathered here. Labels show how each source supports the page, and contextual references are kept separate from primary evidence.
IHO Circular Letter 08/2006 (opens in a new tab)
United Nations Digital Library — General Assembly resolution A/RES/60/30 (opens in a new tab)
International Hydrographic Organization — World Hydrography Day (opens in a new tab)
International Hydrographic Organization — World Hydrography Day (opens in a new tab)
Intergovernmental Authority
International Hydrographic Review — 100 years of international cooperation in hydrography (opens in a new tab)
Understand it, compare it, then explore further
Start with the most common factual questions, then compare closely related observances and explore useful connections.
Frequently asked questions
When is World Hydrography Day?
21 June annually The documented recurrence rule is: 21 June.
Does World Hydrography Day fall on the same date every year?
Yes. It uses a fixed annual date unless stronger evidence changes the pattern.
Is World Hydrography Day an official public holiday?
The reviewed sources verify it within this scope: International Hydrographic Organization / global observance. That recognition does not by itself make it a statutory public holiday; the site only makes public-holiday claims when reliable evidence explicitly does so.
Who established or recognizes World Hydrography Day?
The reviewed sources identify International Hydrographic Organization (IHO) as the proclaiming or establishing body. Current facilitation or coordination is recorded as International Hydrographic Organization Secretariat.
Is World Hydrography Day international or country-specific?
The documented scope is international or global: International Hydrographic Organization / global observance. That does not mean every country treats the date as a public holiday or observes it in the same way.
How is this page verified?
The factual information is checked against reviewed sources, including the date pattern, scope and institutional history. This page was checked on 2026-09-08.
When is World Hydrography Day?
It is observed every year on 21 June.
Who established World Hydrography Day?
The International Hydrographic Organization adopted the observance; the UN General Assembly later welcomed that adoption in resolution A/RES/60/30.
When was World Hydrography Day first celebrated?
IHO Circular Letter 08/2006 identifies 2006 as the first year of the celebrations.
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