World Oceans Day is on Tuesday, June 8, 2027, and it falls on June 8 every year. It’s a United Nations day to celebrate the ocean and encourage people to protect it. Aquariums, schools, scientists and communities around the world hold events.
When Is World Oceans Day?
It’s always June 8. It’s an international observance, not a U.S. federal holiday. You’ll also see it called World Ocean Day.
How Did World Oceans Day Start?
The idea dates to 1992 and the UN conference on environment and development in Rio de Janeiro, often called the Earth Summit. Groups marked the day informally for years after that.
In 2008, the UN General Assembly made June 8 the official World Oceans Day. The first official observance followed in 2009.
Today, aquariums, research institutions, businesses, community groups and governments organize events. Together they “mobilize millions of people around local and global events,” the UN says.
Why Do Oceans Matter?
The UN says the ocean covers over 70% of the planet and produces at least 50% of its oxygen. It also absorbs about 30% of the carbon dioxide produced by humans.
It supports jobs, too. An estimated 40 million people are expected to work in ocean-based industries by 2030, from fishing and shipping to tourism and energy. The day aims to raise awareness of these benefits and of everyone’s responsibility to use ocean resources sustainably.
How much do we know about the ocean?
Less than you might think. As of April 2026, only 28.7% of the global seafloor had been mapped with modern sonar, NOAA reports. About 56% of the seafloor under U.S. waters had been mapped.
Explorers have seen less than 0.001% of the deep ocean floor. That’s one more reason the day encourages curiosity and care.
The 2026 theme
The UN’s theme for 2026 was “Reimagine: Beyond the world we know, a new relationship with our ocean.”
How to Celebrate World Oceans Day
- Join a beach or river cleanup: trash in rivers often ends up in the ocean.
- Cut single-use plastic: carry a reusable bottle and skip plastic straws and bags.
- Choose seafood carefully: look for sustainably caught or farmed options, and ask your fish counter where the seafood came from.
- Visit an aquarium: many host special talks and activities around June 8, so check local listings before you go.
- Watch an ocean documentary: learn about coral reefs, the deep sea or marine migration.
- Use reef-safe habits: don’t touch coral or disturb wildlife when you snorkel or dive.
- Teach kids: map the path from your local storm drain to the nearest ocean.
- Follow a research ship: NOAA and other groups livestream deep-sea dives online.
- Use less fertilizer: runoff from lawns can feed algae blooms downstream.
- Support an ocean group: donate to or volunteer with a local marine conservation organization.
Frequently Asked Questions
How much of Earth does the ocean cover?
Over 70% of the planet’s surface, according to the UN.
How much of our oxygen comes from the ocean?
About half, NOAA says, mostly from plankton. One tiny bacterium, Prochlorococcus, may produce up to a fifth of the oxygen in the biosphere.
Is it World Ocean Day or World Oceans Day?
Both names are used. The UN General Assembly’s designation uses “World Oceans Day.”
Can people far from the coast help?
Yes. Litter and runoff travel down rivers to the sea, so cleanups, careful lawn care and less plastic help wherever you live.