Background <p>Despite robust evidence on the effectiveness of exercise therapy care as a supportive strategy in cancer care, access for cancer patients remains limited across Germany. This is due to a lack of renumeration opportunities, insufficient knowledge, and the absence of integrated provider networks. Existing care services have mainly arisen from individual initiatives and the unwavering commitment of sports science pioneers, who devoted their time, energy, and expertise to developing better methods of care. This study analyses the informal provider networks in the emerging field of exercise therapy care and research, focusing on recurring patterns of interaction between exercise therapy providers and medical professionals that enable patient access to exercise therapy care.</p> Methods <p>This study employed a combination of qualitative network analysis and contextual analysis. A total of <i>n</i> = 31 qualitative interviews were carried out with representatives from the provider networks of exercise therapy care within seven comprehensive cancer centres (CCCs) to explore current patterns of care. The interview data were analysed using qualitative content analysis following Kuckartz, supported by MAXQDA software. Contextual analysis was supported by a survey of key informants (KIs) from exercise therapy care units in CCCs (<i>n</i> = 7) to collect data on patient flow and CCC characteristics.</p> Results <p>We identified seven recurring relational patterns of operation that facilitate patient access to exercise therapy care within care networks. These patterns include mutual recognition from previous projects and shared facilities, improved accessibility to exercise therapy care options, the development of reciprocity between supportive services, raising patient awareness and sensibilisation through existing patient navigators, planning for patient needs via structured screenings for supportive services, collaboration with medical care, and the sharing of knowledge through informational events for healthcare providers.</p> Conclusion <p>Integrated provider networks of exercise therapy care have developed informally, resulting in structural fragility and limited robustness. As long as the effectiveness of exercise therapy care remains research-driven rather than embedded in standard care pathways, these networks remain vulnerable. Establishing formal policies and stable reimbursement mechanisms is essential to institutionalising network ties; strengthening social capital; and ensuring resilient, sustainable access to exercise therapy for all cancer patients.</p> Trial registration <p>ClinicalTrials.gov (Clinical Trials Identifier NCT06185777), December 29, 2023.</p>