Purpose An increasing number of people affected by cancer (PABC) are living longer lives as treatment continues to advance. There is growing evidence for physical activity (PA) supporting health in this population before, during and after cancer treatment, but PA advice is not part of usual care. This study investigates views of frontline oncology healthcare professionals (HCPs) in one NHS teaching hospital in England to understand the role of PA advice across cancer services. Materials and methods This was a qualitative study interviewing HCPs and using thematic analysis. Results Four main themes were identified: 1. Awareness of the roles of PA in cancer; 2. Patient-specific factors in rehabilitation; 3. Cancer-specific factors in rehabilitation; 4. Barriers and opportunities to integrating PA within usual care. HCPs’ awareness of the role of PA in cancer rehabilitation was low overall and PA was found not to be embedded within rehabilitation. Contrastingly, there was awareness of PA’s potential to impact disease and treatment-related outcomes positively. Ideas for PA integration included training for staff and giving PA advice within consultations. Conclusions Low awareness of benefits of PA-based rehabilitation and lack of integration in usual care contrasted with HCPs’ interest in this area’s potential. Training HCPs to begin the conversation with patients affected by cancer in teachable moments may increase patient access. Implications for rehabilitation Integrating physical activity education and training for trainees and existing healthcare professionals workforce would help embed physical activity into routine clinical practice. Brief advice intervention training during every consultation, such as providing relevant individualised information and signposting, can be impactful. Physical activity within a broader cancer rehabilitation programme should be integrated as standard for every cancer patient. Individualised plans may include prehabilitation, restorative rehabilitation and palliative rehabilitation. Patient preferences and the patient experience should continue to shape service design. There is a need to ensure physical activity advice is consistent throughout healthcare settings and not fragmented between primary, secondary and tertiary care.