Background: Physical activity (PA) is a well-established therapeutic modality for the maintenance and improvement of long-term health in cystic fibrosis (CF). Health care professionals (HCP) play a significant role in the promotion of PA behaviours. Limited research exists investigating the extent of PA prescription within CF care. This study aimed to identify Irish HCP i) knowledge and practice of prescribing PA, ii) motivation and barriers of PA prescription; and iii) proposed strategies to optimize PA promotion and prescription in CF populations.Methods: 48 HCP (physiotherapists n=24, other n=24) from six CF centers in Ireland and members of the national physiotherapy clinical interest group completed a 30-item online survey. Results: Most HCP (81%) acknowledged that discussing PA with CF patients was part of their professional role. Almost all physiotherapists (95%) reported having sufficient knowledge regarding PA prescription, compared to 17% of other HCP. All physiotherapists reported discussing PA at every patient interaction, with 81% employing the current consensus guidelines, compared to 33% and 5% of other HCP, respectively. Among the most common barriers reported by HCP to prescribing PA to their CF patients were; lack of motivation and compliance among patients to adhere to PA advice, limited availability of PA programmes to refer their patients to, limited time with patients during clinic visits, lack of knowledge regarding PA prescription for CF care, and patients’ health status deeming PA inappropriate. Three-quarters of HCP reported a need to improve PA services for CF patients in Ireland.Conclusion: As people with CF are living longer, it is imperative that HCP are expanding their scope of practice to consistently include discussions around PA at every patient visit, as physical fitness has been shown to be a key predictor of longevity and quality of life in patients with CF. Formal educational opportunities in the form of continuing professional development programmes, with respect to PA prescription for CF populations, are warranted for CF HCP to optimize long-term patient management and outcomes. There is also a need to introduce or enhance motivational interviewing during patient interactions, to elicit positive PA behaviour change.