Hi, I’m glad to reply to your inquiry.
Which day are you planning to climb Mt. Fuji?
At Mt. Fuji, the climbing season is very limited and so basically there are always many people to climb.
Especially Saturdays are always very crowded with so many climbers.
In addition, August 11 and the following week is kind of major vacation week in Japan, so that it will be also quite busy. Therefore, if it’s possible, it would be much better to avoid those days.
Just for your information, I put a website which provides general information in English about Mt. Fuji climbing. You can also see some foto showing how’s like at the summit of the mountain and the trails during climbing season. http://www.fujisan-climb.jp/en/basic/index.html
Hope you enjoy your climb and have fantastic experience!