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MonJul 21

Marine Day in Japan – July 21, 2025

Marine Day in Japan takes place on the third Monday of July; it falls on July 21 this year. Marine Day is a Japanese national holiday that aims to thank the ocean for its bounty. Considering that Japan is a maritime nation, the country and its people are heavily dependent on the ocean. On this day, many Japanese people make a trip to the beach and enjoy ocean-related festivities. Called ‘Umi no hi,’ the date of Marine Day also generally coincides with monsoons in mainland Japan. The date of the festival was moved around in 2020 and 2021 due to the Tokyo Olympics, Marine Day is set to go back to the regular schedule.

Marine Day, also known as “Sea Day, is a day when the island country of Japan expresses its gratitude to the seas and oceans. Marine Day only became a national holiday in Japan in 1996. Since 2003, it has been observed on the third Monday of July.

Before 1996, it was known as Marine Memorial Day and was not a federal holiday. Water is undeniably essential to our survival. As a result, ‌we should be grateful for our oceans, lakes, and rivers. According to studies, taking the time to consciously practice thankfulness can make us happy, reduce our blood pressure, and do other things. Japan is the world’s only country with a public holiday dedicated to ocean blessing.

History of Marine Day in Japan

Communications Minister Shozo Murata established the day in 1941 to commemorate the Meiji Emperor and his 1876 voyage on the Meiji Maru, an iron steamship built in Scotland in 1874. The excursion included a trip across the Tohoku region, boarding a lighthouse boat in Aomori, and stopping briefly in Hakodate before returning to Yokohama on July 20 that year. It was not, however, designated as a national holiday until 1995, when it became the first summer holiday. The day was also established as a festival to express gratitude for the sea’s blessings, to recognize its significance, and to pray for Japan’s success as a maritime nation.

Initially, the day was known as Marine Memorial Day, announced by Communications Minister Shozo Murata back in 1941. The day was meant to honor the Meiji emperor and his 1876 voyage in the iron steamship called the ‘Meiji Maru.’ The emperor had sailed around the Tohoku region. Marine Memorial Day was made a national holiday in 1995 and became the first holiday during the summer months. The holiday was moved to the third Monday of July in 2003 as part of the ‘Happy Monday’ revisions to holidays that established extended weekends from most public holidays in Japan. It was the first summer vacation on the Japanese calendar, and it coincided with the end of the rainy season. As a result, it is a popular time to visit beaches and participate in various water sports.

In Japan, Marine Day is a significant holiday. Why? Perhaps this is due to Japan’s profound relationship with the land and the waters, both of which are significant components of Shintoism. Because Japan comprises roughly 6,000 tiny islands, most of us can easily witness the recreational and health benefits of the water. Marine Day is one of several nature-themed holidays, which also includes Greenery Day and Mountain Day.

An additional objective of the holiday was to express gratitude for the gifts of the sea and to pray for Japan’s prosperity. It is seen as the official start of the summer season for students, and the three-day weekend allows families to spend time with each other whilst celebrating the day. On this day, families visit beaches to swim, snorkel, surf, dive, or simply spend time on the shore. People also participate in events like mud-ball throwing, which helps break down and eliminate sea grime. Several aquariums across the country also host water-related events.

Being an island nation, Japanese culture, history, society, and identity is closely linked to the ocean. Marine resources have been widely utilized in Japan. Most edible species of marine life have played some role in Japanese culture. As per archeological evidence, fish and shellfish were the mainstays of the diet of the earliest inhabitants of Japan.

Marine Day in Japan timeline

10,000 B.C.
Jomon Era

The earliest inhabitants of Japan begin eating fish.

1876
Meiji Maru

The Meiji emperor goes on a voyage in the Meiji Maru.

1941
Marine Memorial Day

Marine Memorial Day becomes a holiday.

1995
First Observed Marine Day

Marine Day becomes a nationally recognized holiday in Japan, and its name is appropriately changed to its current one.

2003
The Date Officially Moves

Marine Day moves from July 20 to the third Monday of the month, allowing Japan to celebrate the seas over a three-day weekend.

2020
One-Time Move

The holiday is observed on Thursday, July 23, 2020, as a one-time special accommodation to assist with the inauguration of the Tokyo Olympics.

2003
Happy Monday System

Marine Day gets shifted to the third Monday of July.

Marine Day in Japan FAQs

Is Marine Day a public holiday in Japan?

Yes, it is!

What is Japan's biggest holiday?

The most important holiday in Japan is New Year or ‘shogatsu.’

What religion is Japan?

Shintoism and Buddhism are the two major religions of Japan.

How to Observe Marine Day in Japan

  1. Read about Japan’s relationship with the ocean

    To understand Marine Day in Japan. One needs to understand just how central the ocean is to the culture. Read up on it!

  2. Visit the ocean

    Do you live near a beach? Maybe go and spend the day at the ocean. For students, Marine Day is the unofficial start of summer, and many people use this summer break to spend a day at the beach. Odaiba, Yokohama, Kamakura, Enoshima, and Chiba are just a one-hour train ride from Tokyo J.R. Station and are some of the easiest sea-front destinations to visit for beaches and ocean views.

  3. Visit an aquarium

    National aquariums host one-of-a-kind events, water sports competitions, water performances, and sea-themed cultural activities. Japan's Maritime Self-Defense Force decked out their ships with flags and banners, to commemorate the anniversary.

5 Interesting Facts About Japan

  1. It covers over 70% of the Earth

    With the ocean covering so much of the Earth's surface, it's clear how important these marine areas are to the planet and how much more there is to be discovered.

  2. Aquatic life makes up the majority

    The seas are home to a staggering 94% of all living species on the planet.

  3. 5% of the ocean has been explored

    According to the Ocean Service, humans have only explored around 5% of the world's waters.

  4. The longest mountain chain is underwater

    The Mid-Ocean Ridge, the world's longest mountain range, is nearly completely submerged beneath the sea, stretching over 40,389 miles.

  5. Marine plants produce over 70% oxygen

    It is estimated that marine plants, almost entirely made up of marine algae, produce between 70% and 80% of the oxygen we breathe.

Why Marine Day in Japan is Important

  1. It shows our gratitude to the ocean

    Water is undeniably necessary for our survival. We should all be thankful for our oceans, lakes, and rivers.

  2. It encourages us to help maintain its natural purity

    The festival is marked by villagers tossing purifying balls of dried mud into the lake. The efficient microorganisms (E.M.) present ‌aid in the removal of hazardous substances from the seafloor.

  3. It raises awareness of the environment

    On Marine Day, besides tossing special E.M. mudballs into the water to remove muck and slime, other localities hold beach cleanup programs on this day. Their valuable contributions encourage the public to take more care of our environment and preserve our natural resources.

Marine Day in Japan dates

Year Date Day
2022 July 18 Monday
2023 July 17 Monday
2024 July 15 Monday
2025 July 21 Monday
2026 July 20 Monday