Tromtö nature reserve is located on a headland at Tromtöfjärden between the road towards Hasslö and Nättraby in Ronneby municipality.
The nature reserve consists largely of old oak and beech forest and is 1,242 ha, of which 374 ha is land and begins at Hjortahammar's burial ground on the road to Hasslö.
The peninsula has been part of the manor landscape that belonged to the Johannishus estate.
The nature reserve is rich in insects, including ekoxes and wood mushrooms, some of which are rare, such as the saffron stickleback, cake stickleback and sea stickleback.
At the outermost headland, Tromtö nabb, there is a beautifully situated natural harbor with pontoons and room for over 40 leisure boats. The harbor is operated by Karlskrona Navigationsällskap.