Udzungwa National Park, unlike most other national parks in Tanzania, is a high forest area and a place for walking. It is situated along the major fault line delimiting the eastern side of the Southern Highlands. The predominantly westerly winds here have to rise to higher and cooler levels with frequent rains as the result. The vegetation is therefore different from the usual woodlands; it consists of high and dense forest. It is very unusual in Africa to have continuous forest as here, from as low altitudes as about 200 m a.s.l. up to more than 2,000 m. with a gradual change of tree species composition.
The Udzungwa forest is part of the so called Eastern Arc, which extends from the Southern Highlands through the Uluguru and Usambara mountains (see Lushoto) nothwards to Pare. The forests in the Eastern Arc are known for their very high biodiversity. The Usambara violet (Saintpaulia) has one of its most southwesterly occurrences in Udzungwa. Three monkeys, Sanje crested mangabey, the Matundu galago and the Iringa red colobus, are found only in Udzungwa. Visitors in the park are likely to see at least the red colobus.
Walking is permitted along prepared trails. A guide is compulsory and obtained at the park gate near Mangula. Fees are paid at the same place. The short Prince Bernhard trail is 1 km of easy walking to a waterfall. A longer trail leads up to Sanje Falls where there are three consecutive waterfalls. Below the upper two swiming is possible and higly recommendable in the stream, except after heavy rains when water level can be high. There are also longer trails including camping. Note that slopes are steep and that the trails can be slippery and exhausting.