Part of Pico Parana State Park lies within Antonina municipality, protecting a steep section of Atlantic Forest in the Serra do Mar. The park's high ridges are for serious hikers, but even from town the mountain backdrop is part of Antonina's identity.
Treat it as a nature excursion rather than a casual stroll. Trails in this region are muddy, steep, and weather-dependent, and a local guide is sensible if you are heading beyond well-used access points.