Climbing Mount Fuji - nice choice.
Peak season is mid-August during Obon week. In busy periods, it’s recommended to reserve a climbing slot in advance (around 3,000 yen per person).

The classic route is the Yoshida Trail:
Starting point (5th Station): ~2,300 m
Ascent time: 5–7 hours
Descent time: 3–5 hours
Sunrise: visible from this side
Trail fee: 2,000 yen per person
Daily limit: 4,000 climbers

The trail itself isn’t technically difficult, but conditions can include strong winds and steep sections. The main challenges are the length of the climb and the thinning air as you approach the summit.

Recommendations:
If possible (and it’s not easy to book), split the climb into two days—reach the 7th or 8th station and stay overnight in a mountain hut. This allows you to catch the sunrise around 04:30–05:00, when visibility is usually best.
Trails are closed for entry between 16:00 and 03:00 unless you have a hut reservation. A one-day climb is possible - but physically and mentally demanding.

Essential gear:

Proper hiking boots with ankle support
Warm thermal layers (temperatures can drop below 0°C at the summit)
Rain gear (weather changes quickly)
Gloves (for warmth and grip)
Headlamp (for night climbing)
Food, water, and trash bags
Cash (for huts and food along the way)

Etiquette:

Do not pick plants
Do not collect stones
Camping outside designated areas is not allowed

Costs:
At the start, there’s a 1,000 yen conservation fee for trail maintenance.
The Yoshida Trail has an additional 2,000 yen fee.

Altitude sickness:
Many climbers experience altitude sickness - symptoms include headaches, dizziness, and nausea.
To reduce risk:

Listen to your body and allow time to adjust
Climb slowly with regular breaks
Stay hydrated
Use oxygen stations (available between the 5th–8th stations)

If symptoms persist and oxygen doesn’t help, it’s strongly recommended to descend rather than continue.

In the image: sunrise from the summit 🌅