Yes, it is physically possible to "bullet climb" Mt. Fuji in a single day, but it is officially discouraged and increasingly restricted for safety reasons. A one-day climb typically involves starting at the 5th Station in the early morning and returning by evening, or climbing through the night to see the sunrise. However, in 2026, authorities have implemented strict daily quotas (4,000 climbers per day on the Yoshida Trail) and mandatory "gate closures" between 4:00 PM and 3:00 AM for those without a mountain hut reservation. This is to prevent "bullet climbing," which significantly increases the risk of altitude sickness, hypothermia, and exhaustion-related accidents. For a safer and more enjoyable experience, most hikers book a 2-day trip, staying overnight in a mountain hut at the 7th or 8th station before summiting for the sunrise. If you insist on a one-day trip, you must be in peak physical condition and pass through the trailhead gates before the afternoon curfew.