Friskalanlahti (Friskala bay) in Hirvensalo is mostly protected area. The bay is part of the national Waterfowl Habitats Conservation Programme and Natura 2000 network. In addition to the waters, a wide reed bed, pastured waterside meadows and two grove patches are included in the nature reserve.

Friskalanlahti is known as a birdwatchers’ destination. Over 50 bird species nest in Friskalanlahti and some rare nesting species, such as the great reed warbler (Acrocephalus arundinaceus) and the bearded reedling (Panurus piarmicus), can also be spotted. Birds can be observed from the bird watching tower located on the southern shore.

Two parking lots have been arranged for the visitors of Friskalanlahti, and they can be found from the beginning of Vihtilähtie and from Rauhaniementie.