Next to the Hanhipuisto park in the River Kokemäenjoki estuary is the Polsanluoto islet that remains in a natural state.
The first nature trail was built on the Polsanluoto islet with duckboards in the early 1990s. In 2017, the duckboards were thoroughly renovated. A bridge was built in the upper course for crossing the water, while a hand-operated ferry was built in the lower course. Unfortunately, it is out of order for summer 2018.
In 2017, the Polsanluoto islet was nominated as the first Mielipuisto in Pori. When you enter a Mielipuisto, it improves your mood. Pori’s first Mielipuisto was opened on the local nature day that was celebrated on Saturday 17 June 2017 on the Polsanluoto islet and in the Kirjurinluoto Park. The idea of naming the park and organising the event came from the Satakunta Association for Mental Health. The association would like to remind everyone that even a short walk in the woods is better for you than an hour in therapy. Having a natural-state spot for relaxing this close to the city centre is extremely valuable in Pori.