Purpose: Although governing bodies urge the importance of integrating exercise into routine cancer care, facilitators to implementation have not been systematically identified and collated. This review aimed to summarise facilitators to implement exercise services within real-world settings. Methods: A systematic review of qualitative, quantitative, and mixed-method studies was conducted (three databases, 13th September 2024). Reports were included if they documented the implementation of co-located exercise services (delivered onsite within cancer centres) or referral pathways to external exercise services from cancer centres. The updated Consolidated Framework for Implementation Research (CFIR 2.0) was used to code and synthesise facilitators. Results: Of 8544 search results, 28 reports (full-text articles) describing 29 implementation efforts (structured initiatives to integrate an exercise service within a cancer hospital or centre) were included. One hundred and sixty-four facilitators were identified across all CFIR 2.0 domains. Facilitators existed within all CFIR 2.0 domains; inner setting (30%), implementation process (27%), innovation (21%), individuals (15%), and outer setting (7%). The most frequent CFIR 2.0 constructs identified were (i) access to knowledge and information, (ii) engaging recipients and deliverers, (iii) individual motivation, (iv) innovation adaptability, (v) reflecting and evaluating on the innovation and implementation. Conclusions: The implementation of exercise services within cancer settings is influenced by an interconnected network of facilitators, with an organisation’s resources and willingness playing a central role. This review provides a generalised blueprint of facilitators and considerations to guide stakeholders in their own exercise oncology contexts. Implications for Cancer Survivors: This map of facilitators provides potential opportunities for clinicians, policy makers, and researchers, to advance efforts to embed exercise in routine cancer care, so that all people living with or beyond cancer have the opportunity to benefit from it.