The peninsula covers an area of about 100,000 square kilometres (38,610 sq mi). The north coast is steep and high, the southern is flat. In the west part of the peninsula there are two mountain ranges: the Khibiny Mountains, and the Lovozero Tundra, the latter with points up to 1,120 metres (3,675 ft) in height. In the central part of the peninsula lies the Keyvy watershed.

Because the last ice age removed the top sediment layer of the soil, the Kola Peninsula is on the surface extremely rich in various ores and minerals, including apatites, alumina sources, iron ore, mica, ceramic raw, titanium ore, phlogopite, and vermiculite, as well as ores of less-common and colored metals. MMC Norilsk Nickel conducts mining operations on the peninsula. The Kola Superdeep Borehole which is the deepest borehole in the world, is located here also, near the Norwegian border.

Despite its northern location, the Kola Peninsula has a relatively mild climate, because of the influence of warm Atlantic currents. The average temperature in January is about -10 °C (14 °F) and about 10 °C (50 °F) in July. The peninsula is covered by taiga in the south and tundra in the north.