Background: Based on a growing body of epidemiological and biomedical studies, physical activity (PA) is considered a cornerstone in type 2 diabetes treatment. However, it is also a practice embedded in daily life and, as such, may produce certain frictions as a topic in health care. The aim of this article is to give in-depth insight into experiences of health care professionals with the delivery of PA counselling to people with type 2 diabetes. Methods: This study is based on in-depth interviews with 24 Dutch professionals providing care to people with type 2 diabetes. They were asked to tell about their experiences with PA in different roles, both in their professional and personal lives. The interviews were audio-recorded and transcribed verbatim. Data analysis followed a narrative approach with not only a focus on what was told, but also on how this was constructed in interaction with the interviewer, the cultural resources that were drawn on and inconsistencies or alternatives that were presented. This narrative focus was used to explore how professionals made sense of their experiences with PA counselling within the wider sociocultural context. Results: While the professionals view PA as a foundation of type 2 diabetes treatment, they experience it to be a tricky subject. Two main areas of tension were identified: (1) the understanding of patient behaviour; and (2) professionals’ views on responsibilities, both on their responsibilities as professionals and their notions on who is responsible for behaviour change. Conclusions: Health care professionals providing PA counselling to people with type 2 diabetes have to navigate between possibilities within the diabetes care framework, options for an embedding of PA in the patient’s lifeworld, and the professionals’ opinions on and experiences with PA and healthy living from their own lifeworld. This makes PA a complex topic of care. Electronic supplementary material: The online version of this article (10.1186/s12913-018-3102-1) contains supplementary material, which is available to authorized users.