The Fuji Five Lakes region is accessible by bus and train from Tokyo station and Shinjuku station so is perfect for either a day trip or, I recommend, a short stay outside of the city.
The five lakes of this area are Kawaguchiko, Saiko, Yamanakako, Shojiko and Motosuko. The five lakes surrounding the North of Mount Fuji and were actually all formed during a previous eruption of Fuji! Each lake offers a unique and stunning view of Mount Fuji, in fact the 1000 note has a picture of Fuji as viewed from Motosuko.
Kawaguchiko is the most famous and developed of the five lakes, the surrounding area offers many hotels, onsen an restaurants as well as the Kachi Kachi Ropeway, which itself offers a great view of Mount Fuji and a lovely hike through the surrounding forest. Music festivals and other celebrations are held around Kawaguchiko during the year, the fireworks festivals are one not to be missed.
Yamanakako is the eastern most of the five lakes and has some of the best views of Mount Fuji, Yamanakako also offers a slightly more thrilling aspect as it is a popular destination for people interested in both water and motor sports such as wind surfing and water skiing.
However lakes is not all this area offers, there is the Chureito pagoda which offers stunning views of Mount Fuji, especially during the sakura or autumn colour seasons. There is also Sengen shrine at the start of one of the five main ascents to Mount Fuji. Onsen’s are popular and you can even get private rooms facing the mountain for an extra charge.
Mount Fuji also created networks of caves during it’s previous erupts, two rather unique caves are the Wind and Ice caves. The temperature in the ice cave is so low that for many years local people stored ice during the summers months, the cave even creates it’s own ice when water drips through the lava from the surface. (I’d recommend a good jacket and shoes if visiting the Ice cave as it can be slippery and sometimes more than 20 degree difference in temperature!).
A final option for this region is to climb Fuji herself, open during July and August hundreds of thousands of people each year make the 5-6 hour climb up to Fuji’s summit, offering amazing views of the whole five lakes region, and sometimes the sunrise itself!