Archipelago, nature reserves and hiking in Trosa – from Kråmö and Nynäs to the Sörmlandsleden trail

Trosa Havsbad, Kråmö and Askö in the archipelago

At the southern tip of Öbolandet, just south of central Trosa, Trosa Havsbad offers a sandy beach, sun-warmed granite rocks, and open views across the archipelago bay. From the beach, a footbridge leads across to the island of Borgmästarholmen, where walking paths loop around the shore—an easy island experience reachable on foot or by bike without needing a boat.

If you want to venture further out to sea, the car-free island nature reserves of Kråmö and Askö are standout destinations. Kråmö features a traditional archipelago village with red cottages, walking paths, rock bathing, a sauna, and rental cabins. Askö houses both Stockholm University’s Baltic Sea Centre and open coastal meadows, pine forests, and long beaches. In summer, boat tours and water taxis depart from Östra Hamnplan in Trosa Harbour.

Nynäs Nature Reserve and the coastal stages of Sörmlandsleden

Further south along the coast, Nynäs Castle and Nature Reserve stretches between Lake Rundbosjön and the bays of the Baltic Sea on the border between Trosa and Nyköping municipalities. It is one of Sörmland’s largest protected nature areas, featuring grazed oak pastures, castle avenues, rocky shores, and miles of walking trails. Beside the castle stands Nynäs Garden with its orangery and seasonal café.

The Sörmlandsleden hiking trail runs right through the municipality on stages 55, 55:1, and 56. The trail links Trosa Harbour and the River Walk with Stensund Castle on the coast and continues through rocky pine forests and coastal landscapes towards Nynäs and Stendörren. Stage 55:1 is a convenient connecting trail that lets you start or finish your hike right in central Trosa.

Town-side forests: Kronskogen-Stenbrottet, Lånestaheden and Tomtaklint

For shorter weekday or weekend walks, several nature reserves sit right next to the towns. Kronskogen-Stenbrottet borders western Trosa directly, offering forest trails through old pine and spruce woodland and a water-filled historic quarry framed by steep rock walls. Just north of Trosa, Lånestaheden features calcareous conifer forest, rich orchid flora, and an Iron Age hillfort overlooking the valley.

Between Trosa and Vagnhärad, Tomtaklintskogen rises with rocky cliffs and old-growth forest, while Köttkulla Nature Reserve in Västerljung parish offers peaceful broadleaf woodland and ancient oaks. Just north of the municipal border, in Södertälje Municipality, Tullgarn Palace and Nature Reserve makes a classic nearby excursion with its royal park, shoreline walk, and bird-rich coastal meadows.