Right after summer break started, we went snorkeling on Okinoshima Island in Tateyama City, Chiba Prefecture.
We went last year and had a blast, so this was a repeat visit for us.
After checking the forecast, I booked a clear, sunny day online.
There seem to be two or three diving shops offering snorkeling tours around Okinoshima, but we went with Marine Snow again, just like last year.
When people think of snorkeling in Japan, places like Okinawa or the Amami Islands usually come to mind, but you can actually do it right here in Chiba’s Minamiboso area, too!
While the ocean isn’t quite as vibrant and colorful as Okinawa’s, this region is said to be the northernmost limit for coral growth—so while it’s not super abundant, you can still spot some! There are also plenty of fish to see.
It’s an easy, accessible getaway—just about a hour and a half’s drive from central Tokyo.
Okinoshima Beach has a free parking area that runs alongside the coastline, but because it’s a popular beach in the Tokyo metropolitan area, it fills up fast.
It gets especially crowded on weekends and holidays, with a high chance of being completely full by 8:00 AM.
On top of that, driving from Tokyo means taking the Tokyo Bay Aqua-Line, which is notorious for traffic jams. Leaving as early as possible is definitely the way to go.
We left home before 5:00 AM and arrived just before 7:00 AM.
There were already lots of anglers around.
Since we got there quite early, we managed to grab a spot close to the beach.
Even so, there were already tons of cars parked in the prime spots right in front of the sand.
I wonder what time those people got there?!
Because the parking lot stretches along the coast, arriving later means you’ll end up parked further and further away from the beach.
If you’re carrying heavy gear like a beach tent, that can be a real hassle.
Okinoshima is an uninhabited, tide-land island with an area of about 4.6 hectares and a perimeter of around 1 km. I only found out later, but apparently, it features submerged Jomon-period ruins from about 8,000 years ago!
I didn’t know at the time, so we missed them. What a bummer…
We’ll definitely give it another shot next year!
When we reached the beach, a few people were already out in the water.
There were also plenty of tents set up.
We set up ours in a nice spot, too.
By the way, the beach huts open at 9:00 AM.
Here’s the shoreline.
The water is so clear!
Since our snorkeling session was scheduled for 9:00 AM, we played in the water for a bit before heading to the meeting point.
I think there were more than 10 participants in our group.
After about 30 minutes of instructions and warm-up stretches, we took a photo on the beach and headed into the water.
We practiced a little more in the shallows before setting off.
Some kids, who were trying snorkeling for the very first time, struggled a bit at first with breathing and clearing water out of the snorkel, but got used to it in no time.
🔍 Click on the image to enlarge.
It was so much fun again this time!
An elementary school boy in our group seemed to know a lot about fish, excitedly calling out all kinds of names as we swam.
After snorkeling, we grabbed lunch at a beach hut and headed back to the sand.
It was much livelier than in the morning!
On the way, we took a stroll toward the rocky area.
The shallow area right before the rocky shore was covered in lots of stones.
🔍 Click on the image to enlarge.
Looking at a map carefully afterward, I noticed several other interesting spots, like shell-collecting points and caves.
We’ll save those for next time, too!
The beach has stones and shell fragments. There are also rocky areas, so marine shoes (water shoes) are recommended.
On the way back, it was right around sunset, so we got off the highway at Kisarazu and headed toward the famous photo spot with the submerged utility poles.
However, even though we got pretty close, every path leading up to them was blocked by “No Entry” signs, so we had to give up.
Still, we got to see a beautiful sunset!
Note: The beach area is closed to the public outside of the Shiohigari (clam-digging) season.
In 2026, the season ran from Friday, March 20 to Sunday, July 5.
Unfortunately, I was just a bit too late—the clam-digging season had already ended.
The bridge in the photo is the Tokyo Bay Aqua-Line.
The countless thin poles sticking out of the water in the foreground are supports used for seaweed (nori) farming.
This photo was taken just to the left of Ushigome Fishing Port, facing the sea.
It turned out to be a really nice spot!
(Note: On August 13th, Chiba Prefecture suffered severe damage from heavy rainfall. Sending our best wishes for a swift recovery to everyone affected.)
