The fact that most people who climb Fuji-san are not climbers is evident in the popular saying: "He who climbs Mount Fuji once is a wise man, he who climbs it twice is a fool." This may also account for the need for supplemental oxygen by some climbers. Another popular saying is that Fuji-san is the most climbed mountain in the world, however, this has recently come under debate with New Hampshire's Mount Monadnock (3,165 feet), with 125,000+ climbers / year, as the challenger.
There are four ascending and three descending YDS class 2 routes to and from the summit, the most popular of which is the Kawaguchiko Route (~4.5 km) from the north. Kawaguchiko means "Lake Kawaguchi" and has the easiest trailhead to reach from Tokyo. The trail initially goes around the mountain clockwise, losing some elevation before ascending to the Sixth Station (Roku-gome) where you join the Yoshida Route to the summit. There is an Anzen Centre (safety center) here. Above the Sixth station you will see many barriers put in place to prevent rockslide as you follow the lava road up past several huts to the Seventh Station (Nana-gome). Follow the switchbacks as the trail stepens beyond the Eighth (aka Old Eighth) stations where you will reach the crater rim and be greated by a pair of lions and a torii gate, Kusushi-jinja. You are now on the northeast end of the crater and you will need to make your way around the crater rim to the summit Tsurugi-ga-mine (3776 m). For the desent route, follow the same route you came up until just below the Eighth Station where the descent track will brach right (east) to follow a less steep path down (this is also the winter ascent route) joining the ascent route at the Sixth Station. The Fuji Suburu Line road to the Fifth Station here is typically open during the winter as is the tourist facilities, making this one of the more popular winter routes.
For information on climbing off-sease, be sure to read the "When to Climb and Ski / Snowboard" section below.
The other routes are the Subashiri from the east, Gotenba (aka Sunahashiri) from the southeast, and Fujinomiya from the south. These are described on the Japan National Tourist Organization (JNTO) Climbing Mt. Fuji Page.
KAWAGUCHIKO (2,305 m) / NORTH SIDE: The Kawaguchiko-guchi Go-gome (Kawaguchiko Fifth Station) trailhead is the easiest trailhead to reach for those coming from Tokyo. From Tokyo, the simplest way to make this trip is to take the bus from the Shinjuku bus terminal (near western end of Shinjuku Station) to end of the Fuji Suburu Line. The direct bus runs three times a day and costs ¥2600 and takes 2.6 hours. Most climbers take the evening 7:30pm bus which arrives at the Fifth Station at 10:00pm so they can start hiking soon after (vs. the two morning buses). This bus runs only from July 10 to August 31 and you should expect an entire fleet of buses to cart would-be climbers off to the mountain from Shinjuku Station. Call 0353-76-2222 to make the necessary reservations. You can also take an hourly bus to Kawaguchiko and then transfer to the Tozan bus (¥1700 1-way, 50 min) to reach the Fifth Station. Once the official season is finished by the end of August, buses from Shinjuku to Kawaguchi-ko run twice per day during the weekends, at 08:45 and 09:45 and back at 15:00 and 16:00. That leaves you 4h 45' to do the round trip to the summit and back, unless you plan to stay in one of the few huts, if any, that remain open (Ref: Hector Garcia Hevia). Of course, you can always take a car or taxi as well. Unlike the Fuji Skyline Road that closes during the winter, you can often find the north side open for tourists to the Fifth Station making this a popular trailhead for winter ascents.
SUBASHIRI (1,980 m) / EAST SIDE: Take the train to Tokaido Honsen line to Numazu Station and then connect to Gotemba Station. At the station you can hire a bus or taxi to take you to Subashiri-guchi Shin-go-gome (Subashiri New Fifth Station) from where you will start your hike. Use the Japan National Tourist Organization (JNTO) road and train map.
GOTEMBA (1,440 m) / SOUTHEAST SIDE: Take the train to Tokaido Honsen line to Numazu Station and then connect to Gotemba Station. At the station you can hire a bus or taxi to take you to Gotemba-guchi Shin-go-gome (Gotemba New Fifth Station) from where you will start your hike. Use the JNTO road and train map.
FUJINOMIYA (2,380) / SOUTH SIDE: From Tokyo, take the Tokaido Shinkansen (bullet train) to Shin-Fuji Station and then drive or take a bus 2 hours through the town of Fujinomiya and up the Fuji Skyline Road to Omote-Fujinomiya-guchi Shin-go-gome (Fujinomiya New Fifth Station). From here you will hike north along the Fujinomiya Track. If you want to hike from the First Station, start your hike in Fujinomiya City's Sengen Gingu, the main Shinto shrine for followers who worship the mountain. The Fuji Skyline Road on the south side of the mountain is closed from December to April so this route is not often used for winter ascents, unless you want to start at the Shinto shrine. Use the JNTO road and train map.
OFF MOUNTAIN / KAWAGUCHIKO - NORTH SIDE / GOGOEN REST HOUSE: Located at the Fifth Station on the Kawaguchiko Route, this is a large log-cabin type lodge that houses a hotel, restaurants, and gift shop. There is also a rest area for climbers. Apparently, this is often open through the winter and is a good location to stay before attempting a winter climb.
OFF MOUNTAIN / GOTEMBA - SOUTHEAST SIDE / FUJI HAKONE GUEST HOUSE: Traditional Japanese accommodations at very resonably prices in beautiful Hakone. Online reservations are available. Also has information for Moto-Hakone Guest House and Sengokuhara Youth Hostel.
CURRENT CONDITION RESOURCES
FAIR WEATHER CLIMB: Since the climbing season always ends on August 27, you can climb immediately afterwards to escape the crowds and shops, but you won't get your branded walking stick. Hiking before the official season in June can mean for some mild, but nice, snow hiking.
WINTER MOUNTAINEERING: Late November to May or June are best times to climb this peak under snow. Be sure to bring your crampons and ice axe as the routes can get icy near the summit. You also have the option of bringing your tent to camp anywhere along the way or at the summit. Bryowan adds:
With snow and/or ice covering the scree it is possible to climb directly to the summit by one of the ridges or snowfields or almost any combination. When glissading, stay alert so as not to pass the fifth station if your vehicle is parked there!
A very enjoyable climb but not one to be underestimated.