The number of wind power facilities (wind farms) has rapidly increased in Germany, with a number of these constructed in forested areas. As most bat species use forests to forage and roost, concerns have been raised in relation to the potentially higher collision risk with wind turbines in forests than in open landscapes. In addition, the standard curtailment algorithms used in open landscapes might not be appropriate in forests. An ample acoustic dataset derived from 193 nacelle height surveys of 130 individual turbines was used to investigate whether bat activity, phenology or species composition differ between forests and open landscapes. The data showed no significant differences between bats in forests and open landscape habitats, but revealed strong regional differences. Overall bat activity increases towards the east of Germany, which is mirrored by an increase of the dominant group of Nyctaloids, whereas the activity of common pipistrelles increases towards the south. These findings suggest that acoustic surveys must be interpreted on a regional and species-specific level. In summary, wind farms within forested areas do not seem not to inherently show higher bat activity at nacelle height, suggesting no increased collision risk for bats in general. However, future studies assessing bat activity at the lowest point of the rotor instead of at nacelle height are urgently needed, as well as studies that include additional variables such as proximity to bat roosts or the age of a forest.