Umi no hi - Japan’s Marine Holiday

What is Umi no hi?

Although it doesn’t exist everywhere, Japan has a sole holiday in which gratitude for the briny deep is expressed. Umi no hi (海の日)  is a holiday celebrated in Japan to honor the ocean and the resources we gain from it; Japan carries a reputation of being a “maritime nation”, so it’s important to acknowledge this identity. The holiday is typically celebrated on the third Monday of July; this year, it will be on July 20th, and many people will partake in different activities to celebrate. The holiday doesn’t just act as an encouragement of appreciation, but it also acts as a promotion of conserving the largest food supplier in Japan. 

The holiday was established in 1941 in commemoration of Emperor Meiji’s return from a Tohoku voyage in 1876 to the port of Yokohama,  and “the expedition was commemorated by naming July 20 ‘Marine Memorial Day’” (Coto Academy). It wasn’t until 1995 that the Japanese government suggested establishing ‘Marine Memorial Day’ as a national holiday dedicated to the sea, and in turn giving it the new title of “Umi no hi”.

The holiday is celebrated on a Monday due to Japan’s “Happy Monday System”, a law established in Japan to move a number of public holidays to Mondays. Umi no hi was moved to the third Monday of July in 2003 to allow Japan to appreciate the oceans to the fullest over a three-day weekend. In addition to Umi no hi, July is designated as “Ocean Month” in Japan.

Significance of “Uminohi”

Japan prides itself on beingas a “Maritime Nation”, especially since it is made up of thousands of islands and it depends heavily on the sea for transportation, trade, fishing, and food culture. The ocean is central to daily life and survival: “From seafood cuisine like sushi and sashimi to maritime trade and fishing, the ocean sustains Japan’s economy and traditions” (Coto Academy). With this pride comes religious beliefs as well: there are Shinto beliefs that nature must be respected; this respect must be given since the ocean is a source of life and prosperity that helps Japan flourish and thrive as a country. Located by the coast are shrines such as the Itsukushima Shrine in Hiroshima that emphasize the spiritual bond between those who appreciate Shintoism and the ocean.

Itsukushima Shrine

 The holiday is also significant from an outside perspective due to its uniqueness: Japan is the only country with a holiday solely dedicated to the ocean. Umi no hi highlights the importance of sustainable use of ocean resources and community involvement in protecting Japan's seas and reinforcesenforces one’s responsibility to protect this provider. It’s important to note that this holiday isn’t celebrated throughout all of Japan. Since, since Nara Prefecture has no sea, the third Monday of July is designated by ordinance as “Nara Prefecture Mountain Day and River Day” (HH JapaNeeds). 

Events 

There are many different celebrations held during Umi no hi: “Since 1986, various events have been held in major port cities as “Marine Festa,” including commemorative ceremonies, celebrations, and symposiums” (HH JapaNeeds). Along with that, many people take trips to the beach to celebrate, and will participate in activities such as swimming, surfing, snorkeling, and diving. Family vacations are also commonly paired with aquarium visits.

 A more niche activity includes “mudball throwing”, an activity that has gained popularity within the last few years. The activity holds heartfelt meaning to it; you can give back to the ocean in a literal way by throwing dried mud balls filled with ‘Effective Micro-organisms’ (EMS) into the water, assuming you don’t mind getting your hands a little dirty in the process. Effective micro-organisms are “naturally occurring microbes” such as lactic acid bacteria, yeast, and phototrophic bacteria (EM Research Organization). These micro-organisms collectively strengthen or expedite natural processes by suppressing harmful bacteria to restore environmental balance.

Knowing this, it’s safe to say that this activity doesn’t just act as a source of entertainment, but it also has ecological benefits since these balls of mud help to “break down and eliminate sea grime” (Coto Academy). In addition to these activities, there is an Odaiba lantern festival where “hundreds of magical, tethered LED sky lanterns filled with helium are simultaneously released into the night sky over Tokyo Bay with the Rainbow Bridge as the backdrop” (TokyoOdaiba.net). Whether you are in Japan or not, I strongly encourage you to consider expressing your appreciation for the ocean on this day, as it plays a huge role in our lives and it is home to the most extraordinary and complex ecosystems on the planet. 

Works Cited

“What Is the Origin of Marine Day(Umi No Hi)? | HH JapaNeeds.” HH JapaNeeds, 23 June 2022, https://hh-japaneeds.com/meaning-of-uminohi/. Accessed 17 July 2026.

Kanpai. “Umi No Hi.” Kanpai Japan, Kanpai!, 22 July 2025, https://www.kanpai-japan.com/japan-lifestyle/umi-no-hi. Accessed 17 July 2026.

隆明 松崎. “🌊 Marine Day (Umi No Hi) – Japan’s Sea Day on July 21.” 京のマチカド Tabigokoro-旅心-, 21 July 2025, https://matikado-tabigokoro.jp/en/blogs/kyoto-blog-post/%f0%9f%8c%8a-marine-day-umi-no-hi-japan-s-sea-day-on-july-21?srsltid=afmboormx-sprytijz5loo_kfbjv1zf3ghi5z65ilwiki0kzbuous91n. Accessed 17 July 2026.

“Marine Day (海の日): How and Why Japan Pay Homage to the Oceans -.” Coto Japanese Academy, 17 July 2017, https://cotoacademy.com/japan-national-holiday-oceans-day/. Accessed 17 July 2026.

“Marine Day in Japan: Discovering Umi No Hi and Its Unique Celebrations – Japan Rail Club.” Japan Rail Club, 20 July 2023, https://www.japanrailclub.com/marine-day-how-it-is-celebrated-in-japan/. Accessed 17 July 2026.

“The Nippon Foundation.” The Nippon Foundation, 17 Feb. 2025, https://en.nippon-foundation.or.jp/. Accessed 17 July 2026.

“What Is EM | EM Research Organization (EMRO).” EM Research Organization (EMRO), 2025, https://emrojapan.com/em/what/. Accessed 17 July 2026.