Suga, Natural Monument

What is the definition of hot springs?

As long as spring water is hot, can we call it a hot spring?

Japan has the Hot Springs Act.

According to the law, the natural monument in a southern island can be called a hot spring.

This place is registered as 500 Important Marshes in Japan, because of some endangered species of seaweeds.

Please make sure not to destroy the nature.

The Hot Spring Act

Let’s browse the Hot Spring Act, which Onsen Island, Japan established.

In summary, spring water and gas (steam) can be recognized as a hot spring, only if any conditions described below matches.

  1. It is hotter than 77 degrees F.
  2. It contains any particular materials (18 types, hydrogen ion for example).
  3. It contains greater than one gram of any materials (except for gas) per one-kilo gram as a whole.

As you may be aware, even if it is not hot, it can be called a “hot” spring, as long as it meets other requirements.

Hot springs in Okinawa

After World War II, Okinawa had been governed by the United States for 27 years.

Road Sign

I heard, in this beautiful island, that there are hot springs.

In 1972, on the day Okinawa returned to Japan, it was registered as Japanese Natural Monument.

The name is “Suga” (in English, the Salt River), which is located along an unremarkable highway.

Explanation Board

You will find a mystery, which more than twenty gallons per a second of salt water is flowing, even though here is higher than the ocean surface.

There are only two cases seen in the world; the other is in Puerto Rico.

Under the mangrove jungle, there is a stream with small fishes.

Not look much like hot springs

If you ascend the stream, you will find a waterhole.

From gaps of the rocks, a spring is gushing out.

Water Outlet

Referring the Hot Spring Act described above, it contains salt and you may call it a hot spring.

Now take a bath.



Even though it is in a southern island, the water temperature is too cold to soak in December.

Indeed, it is salty, but it tastes like water-thin seawater.

In the hot spring river, I encountered the edge of hot springs.

It seems to be more reasonable to say the definition of a hot spring is just spring water that is hot.

Suga, Motobu-cho, Okinawa, Japan
Official WebsiteNO

Related hot springs

The world of hot springs is, actually, not so simple.

Shibu Tatsunokan

Shibu Tatsunokan, Tateshina Onsen, Nagano, Japan

When you jump into 78 degrees F of cold spring being poured from the ceiling, screaming out, you will see a whole new world of hot springs.

Leave a Reply

Ken Springfield