Low levels of physical activity among adolescent girls are a cause for concern. Examining girls' physical activity perceptions and motivations through in-depth qualitative research allows for greater understanding of the reasons behind their physical activity-related choices. Forty-seven girls aged 14 to 16 years participated in exploratory focus group discussions. Thematic analysis was carried out in which data were analysed inductively using a constant comparison method. The findings illustrate the extent to which adolescent girls' physical activity participation is affected by social influences and perceived societal norms. Furthermore, changing priorities throughout adolescence mean that physical activity is deprioritized, with many girls stating that they cannot be bothered to take part. Recommendations to increase participation include encouraging parental support, introducing peer mentoring schemes involving girls who enjoy and regularly participate in physical activity and providing activities for adolescent girls that are fun, informal in nature and involve participation with friends.