【Kansai・Wakayama】Do you need to watch out for Jellyfish during Obon? Tips on Enjoying the Sea in Wakayama in August

The Sea During Obon: Points to Watch out for

Summer vacation is here, and of course you want to have fun at Japan's beaches. Many people think that "During summer vacation, I want to enjoy festivals, fireworks, and take a swim at one of Japan's beaches!"

However, in Japan there is a long-standing belief that you shouldn’t go swimming in the sea around Obon (mid-August, roughly August 15).

Obon is a traditional Japanese festival to honor the spirits of ancestors. You might wonder, “Is this related to spirits?” But in reality, the reason comes from something scientific: JELLYFISH! During this season, jellyfish increase in number.

So, what exactly is the reason for this?

Why Do Jellyfish Appear?

It’s not that jellyfish suddenly show up after Obon. In fact, they are always present in the sea throughout the year. But baby jellyfish are very tiny and nearly transparent, so they go unnoticed.

From July to August, when seawater warms to about 20–30°C, jellyfish grow rapidly. As they mature, their bodies get larger and more visible, and suddenly they start standing out at swimming beaches.

What’s more, not only do local jellyfish grow bigger, but jellyfish from tropical and subtropical seas also ride the Kuroshio Current (a warm ocean current flowing east along Japan) up north, arriving in quiet bays around Japan. Because the Pacific Ocean stays warmer than about 20°C year-round, it provides the perfect conditions for jellyfish to reproduce continuously.

As a result, people often feel, “Suddenly there are so many jellyfish during Obon!” But really, it’s just that they’ve grown big enough to be easily seen.

Safety Tips for Enjoying the Sea

Here’s how to enjoy the sea after Obon safely:

Wearing long-sleeve swim shirts (rash guards) or long pants is recommended to cover your skin and reduce the risk of stings. If stung, first get out of the water immediately to avoid drowning, and then seek medical attention as soon as possible.

If you can see tentacles, don’t touch them with bare hands—use gloves or tweezers to remove them. Be sure to rinse the affected area gently with seawater instead of tap water; the difference in osmotic pressure from tap water can worsen the symptoms.

Even if you avoid swimming, there are plenty of ways to enjoy the beach—walking the sandy shore, dipping your feet in the sea, or just relaxing by the coast. Wakayama is full of safe, beautiful beaches, so you can still have wonderful summer memories.

When it comes to beaches in Kansai, Wakayama tops the list.

Shirarahama Beach

You can’t miss Shirarahama in Shirahama Town. From early morning it’s lively and crowded, with sparkling white sand shining like diamonds. It looks like Waikiki Beach in Hawaii—and for good reason, since the two beaches are actually sister beaches.

Here, people pitch tents on the white sand, sip cold drinks with friends, eat yakisoba, or just sunbathe. You can make amazing memories even without going into the water.

【Information】
Name: Shirarahama Beach
Opening period: Saturday, May 3, 2025 (national holiday) - Monday,
September 15, 2025 (national holiday)
Address: 864 Shirahama-cho, Shirahama Town, Wakayama Prefecture Prefecture

Ubuyu-kaigan

Ubuyu-kaigan, in central Wakayama, is famous for its shallow waters, high transparency, and calm waves, making it especially popular with families.

As you walk down the seawall stairs and see that blue sea spreading out before you, the excitement is undeniable.

【Information】
Name: Ubuyu-kaigan
Operating Period: July 12th (Sat) - August 22nd (Fri), 2025
Address: 717-1 Wakayama Prefecture , Hidaka Town gun, Hidaka Prefecture

Suhara Beach

Suhara Beach is just a ten-minute drive from Yuasa, a historic town known as the birthplace of soy sauce. It feels like time flows slower here, making it a peaceful, healing spot. You can even rent bikes at the tourist center near Yuasa Station and enjoy a ride with sea breezes before relaxing by the ocean.

The broad bay has gentle waves, perfect for beginners trying sea kayaking or SUP. Some courses even include mini adventures like landing on uninhabited islands or exploring caves.

Nearby Yuasa Onsen and Suhara Onsen are perfect for washing off sea salt and sweating out the day, refreshing body and mind.

Since Yuasa is also the "birthplace of soy sauce", strolling through the town and soaking in the rich aroma is a must! After sightseeing, try the local specialty "Soy Sauce Ice Cream"! Yes, you read that right.

At the renovated Yuasa Station Building, you'll also find light meals using local ingredients, such as onigiri. For seafood lovers, don't miss the fresh shirasu (baby sardines) dishes near Yuasa Station! It's drizzled with Yuasa Soy Sauce-- an absolutely delicious local specialty!

【Information】
Name: Suhara Beach
Operating Period: July 1st (Tue) - August 31st (Sun), 2025
Address: Suhara, Yuasa-cho, Arita Yuasa Town , Wakayama Prefecture Prefecture