hydrangea at Sai no mori park

Sai no Mori Iruma Park is a park that is always buzzing – in both senses of the word. For one, you have the constant hum of aircraft, a sound I personally love. Moreover, anytime I have ever visited it, no matter what time of year, the park is always buzzing with people. People walking, playing, shooting hoops, chatting on the benches or lounged on the grass. It’s location in a highly populated suburb, close to Johnson Town, no doubt plays a part in its popularity with locals. In addition, the aesthetics of the park probably add to the appeal.

Sai no Mori Iruma Park

Sai no Mori Iruma Park is located right beside the Japan Air Self Defense Force Iruma Air Base, famed for its annual air show. If you come by car and are using the official car park you will pass a section of the air base where you can see old planes and air force paraphernalia. You can’t go in to the base (without special permission), but there is a clear view from outside and you can even get a photo.

When you visit the park during the day, you can constantly hear planes coming and going. But amazingly you can’t really see them due to the flight path they take. The area around the air base and Sainomori Iruma Park is known for its aviation history. Once upon a time, the American forces operated the Iruma Air Base. However, it was known as Johnson Base at the time. It was returned to Japan in 1973. Just a five minute walk from the park there are remnants of that period in Johnson Town. A short drive away Inariyama Park replaced the former residential area of Johnson Base.

Iruma City’s Oasis

Current day Sai no Mori, which was founded in 1998 as a place for locals to ‘refresh’ in nature. The park is very picturesque with trees in abundance and two lakes, both with fountains in them. However, the fountains aren’t on constantly. They are turned on four times a day for fifteen minutes each time. The park certainly seems to be loved by the locals. Anytime, I’ve ever visited the park is throbbing with people. Its always a lovely feeling to see a park in full use.

But as it is quite small and it has little for children, it is not a park that I visited much when my children were smaller. It does have one small area for kids with two climbing hills suited to toddlers. If I was visiting with children now, I would combine a trip to nearby Fujimi Park which has a great playground. And the kids always love an ice-cream or treat from Johnson Town, which is just across the road. Furthermore, there are plenty of other parks within driving distance.

Sainomori Iruma Park in Autumn

autumn colors / leaves at sai no mori iruma park

However, with all my children in school now, I finally have time to explore places that are not necessarily child friendly. I always wanted to see Sainormoi in Autumn as there are so many beautiful mature trees in the park including poplar trees and metasequoia. Today, I finally got to cross it off my list of places to see in the Autumn in Saitama. The vibrant colors and the buzz in the park certainly made the traffic I encountered on the way worth it! It is expected that the autumn leaves will be good to the end of November.

After offering to take a photo of a couple by one of the two lakes in the park and we got chatting. They had travelled from Tokyo after seeing the park live on TV this morning. As a long termer in Saitama, I do know the park is renowned by locals for its autumn leaves. If it wasn’t known outside Saitama before today, it certainly is now! It is definitely worth a visit if you are in the area. However, unless you are planning to visit Johnson Town or another nearby attraction, I’m not really sure its worth coming a long distance for. I suppose though, Tokyo is just down the road thanks to the Ken-o expressway.

Summer in Sai no Mori park

Added in June 2022: there are water lilies in the park. They are currently in bloom June 17th 2022. The park has quite a few hydrangea around the large lake and also a few around the smaller lake where the water lilies are. As of June 17th 2022, the hydrangea around the larger lake weren’t really blooming. But the Annabelle (white) hydrangea around the smaller lake and the colorful hydrangea near the park entrance were in full bloom.


There are a few things in the park though. For example, there is a barbecue area in the park. It opens from mid March to early November annually. You need to book a place in advance. There is also a nice little rest house in the park which has a food van and a nice area to sit outdoors. Here you will find several vending machines. Like almost every park in Japan, there are toilets.


On Google Maps it is written as Sainomori (one word) Iruma Park.

Address: 2 Chome-2 Koyodai, Iruma, Saitama 358-0001
Phone: 04-2960-1664
Hours: open 24 hours, but the parking lot closes overnight. The official hours are from 6 am to 7 pm.
Cost: Free and parking free
Official website


Sai no Mori park is about a twelve minute drive from the Ken-o expressway’s Sayama-Hidaka Interchange. There were lots of turns to take, but Google did a good job of directing me. If there weren’t so many traffic lights and so much traffic, it would be quicker as its only a distance of about five kilometers. Parking is free and plentiful.

By public transport you can walk from Seibu Ikebukuro Line’s Irumashi station. It takes about 15 minutes on foot from the station to the park.

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