Marine Day, also known as "Umi no Hi" (海の日) in Japan, is a national holiday that celebrates Japan’s ocean and maritime activities. Unlike traditional festivals and holidays that are often associated with specific shrines or temples, Marine Day itself does not have dedicated shrines or religious ceremonies and is a relatively modern holiday established in 1996.
Observed on the third Monday of July every year, Marine Day is the next big holiday that people look forward to after Golden Week in May. If you’re wondering and looking for things to do on Marine Day, here are some common ways people celebrate Marine Day in Japan:
1. Beach visits

Yonehara Beach. Photo by Okinawa Convention & Visitors Bureau
The sun’s out, it’s time to head to the beach! Marine Day falls during the summer season, making it a popular time to head to the beach to enjoy the sun and the ocean. Japan’s coastlines are filled with beautiful beaches, and the weekend preceding Marine Day is usually when people from the cities take to the water for beach trips and water-related activities such as surfing, swimming, snorkelling, and boating.
Best beaches to visit:
- Shirahama Beach (白浜大浜海水浴場), Shimoda, Shizuoka Prefecture
- Shonan Kaigan Park (湘南海岸公園), Fujisawa, Kanagawa Prefecture
- Yonehara Beach (米原ビーチ), Ishigaki Island, Okinawa
2. Fireworks displays

Fireworks displays at Marine Day Nagoya Port Festival. Photo by Nagoya Port Authority
Fireworks festivals, or hanabi taikai (花火大会) are often held during summer, and some of the more exciting ones are held on the Marine Day long weekend. These spectacular fireworks displays are organised near bodies of water, such as beaches, rivers, or lakes, providing a beautiful evening spectacle for spectators. Particularly, the Marine Day Nagoya Port Festival (海の日名古屋みなと祭) draws tens of thousands of crowds annually with its majestic display of fireworks, launched in sequence with a choreography of lights and sound. There’s something about watching fireworks and their reflections on the waters of the sea that makes the whole experience very special.
3. Maritime events

Photo by Pakutaso
Various events and activities related to the ocean take place during the Marine Day weekend, such as the Odaiba Lantern Festival, boat and yacht races, fishing competitions, and other water sports demonstrations. Some skin and cosmetic brands may even take this opportunity to promote reef-friendly sunscreen products, while small groups may even challenge themselves for a beach or river clean-up. In general, these events aim to promote interest in maritime culture and raise awareness about marine conservation.
4. Aquarium visits

Photo by Okinawa Churaumi Aquarium
Marine Day is also an opportunity to visit marine parks and aquariums to learn about marine life. Many aquariums may take this chance to promote educational initiatives to raise awareness about marine ecosystems through special exhibitions, workshops, or lectures.
Best aquariums to visit:
- Churaumi Aquarium (美ら海水族館), Okinawa Prefecture
- Kaiyukan Aquarium (海遊館), Osaka Prefecture
- Enoshima Aquarium (新江ノ島水族館), Kanagawa Prefecture
5. Seafood cuisine
Photo by Pakutaso

Being an island nation, Marine Day highlights the importance of the sea in bringing economic prosperity and cultural wealth to Japan. While specific celebrations and activities may differ from the region or the individual, Marine Day is ultimately a day that serves as a reminder to appreciate and protect the natural beauty of Japan’s seaside.
Header photo by Pakutaso