Nuuksio is the closest national park to Helsinki — and the easiest place to see Finland's classic landscape of old spruce forest, mossy boulders, and small lakes in fast succession. Trails of every length leave from the Haltia visitor centre, the most popular being the Haukkalampi loop (4 km) and the longer Punarinta circuit (8 km). The terrain is rocky and uneven; proper shoes matter even in summer.
The park is reachable on the public bus from Espoo Centre — change at Espoo Station, then take bus 245 toward Haltia. By car it's 45 minutes from central Helsinki. Camping is allowed at designated lean-tos, and the warden cabins offer overnight beds in winter. Autumn brings cloudberries and lingonberries; midsummer offers the famous nightless nights.