https://www.jal.co.jp/flights/en-sg/flights-from-singapore-to-tokyo (JAL Singapore web page as sample)

Fly JAL to maximize your sports vacation in Japan

Japan Airlines is assisting Skiers, Golfers, Divers and Cyclists traveling to Japan.
An Extra Checked Baggage allowance for Sports Equipment (eg: skis, clubs, diving gear and bicycles)
Fly Japan Airlines to enjoy Skiing, Golf, Diving and Cycling in Japan. For a limited time, we are offering an extra checked baggage allowance for overseas travelers bound for Japan with their sports equipment.

HOW TO APPLY
To apply, please contact our contact center no later than one day prior to your flight’s departure date.
In case of a reservation change, please contact our contact center at your location.

DIVING AND UNDERWATER PHOTOGRAPHY EQUIPMENT
1PC of excess baggage and the excess size charge (Fee for Exceeding Free Baggage Size) shall be exempted.
When the weight of checked baggage exceeds the free allowance, the extra charge is applied.

Japan Airlines(JAL) announced the launch of Luxury Diving Tours in Japan for visiting Divers.
The package are either "a Day trip" or a "1 night stay" at a recommended diving locations all around Japan.
1)You will be picked up and down by your english speaking guide, at the airport or at the hotel you are staying.
2)Your guide will also guide you underwater.(Your guide will either be a DiveMaster or an Instructor)
3)(For a 1 night stay Package) A local accommodation is included.

https://www.jal.co.jp/ar/en/guide-to-japan/experiences/diving/  (US)
https://www.jal.co.jp/au/en/guide-to-japan/experiences/diving/  (Australia)
https://www.jal.co.jp/hk/en/guide-to-japan/experiences/diving/  (HongKong)
https://www.jal.co.jp/kr/en/guide-to-japan/experiences/diving/  (S Korea)
https://www.jal.co.jp/sg/en/guide-to-japan/experiences/diving/  (Singapore)
https://www.jal.co.jp/id/en/guide-to-japan/experiences/diving/  (Indonesia)
https://www.jal.co.jp/ph/en/guide-to-japan/experiences/diving/  (Phillipine)
https://www.jal.co.jp/my/en/guide-to-japan/experiences/diving/  (Malaysia)
https://www.jal.co.jp/vn/en/guide-to-japan/experiences/diving/  (Vietnam)
https://www.jal.co.jp/th/en/guide-to-japan/experiences/diving/  (Thailand)
https://www.jal.co.jp/uk/en/guide-to-japan/experiences/diving/  (UK)

Tokyo Divers is now added to our NPO family list. They have many weekend diving tours going to destinations around the Greater Tokyo area.

This was an article published by Xray Magazine February  2022(Issue 110)

As a divemaster in Japan, I have enjoyed diving all around the world, and I will admit that there are many places on earth I would love to revisit soon. But for today, I would like to introduce my home country, Japan, as your next possible dive destination.

https://pdfs.xray-mag.com/articles/Travel_Osezaki_Japan_KenjiIchimura_1…

Pinnacle Diving Company(PDC) has many Youtube videos for Japanese diving site. With collaboration with PDC, we have added "Atagawa" to our list. Have a look and Enjoy!!