Background <p>Older adults are disproportionately vulnerable to adverse outcomes during postoperative care transitions. While evidence-based care transition interventions exist, such as the Care Transitions Intervention (CTI), their core components have not been systematically adapted for surgical populations. Concurrently, geriatric surgery co-management models, such as the Optimization of Senior Care and Recovery (OSCAR) model, improve outcomes but do not address the post-discharge transition. To bridge this gap, we merged the geriatrics-informed, inpatient co-management model of OSCAR with the patient-empowering, coaching-based approach of the CTI to create a novel integrated care transition model - OSCAR-S. We describe the use of implementation science approaches to characterize adaptations and refinements of this merged model to enhance its feasibility and contextual fit for older colorectal surgery patients.</p> Methods <p>Our adaptation process was informed by the ADAPT framework and the Framework for Reporting Adaptations and Modifications - Expanded (FRAME). Guided by these frameworks, we explored stakeholder perspectives to inform the adaptation of OSCAR-S. We conducted a total of 41 semi-structured interviews with 35 healthcare providers, three care partners, and three older colorectal surgery patients. We performed inductive content analysis of suggested adaptations, which were documented and classified using FRAME.</p> Results <p>Applying the ADAPT and FRAME frameworks supported a process that identified core intervention components and optimal adaptations. Interviewees expressed widespread support for the intervention’s core components, particularly the role of the geriatric surgery nurse coach as a critical liaison and patient advocate during the vulnerable post-discharge period and geriatrics-focused assessments and personalized geriatrics care panning in older surgical patients. The adaptations made in response to stakeholder feedback, including adjustments to timing, delivery methods, and communication pathways, enhance the model’s feasibility while preserving fidelity to core elements.</p> Conclusions <p>We systematically adapted and refined the merged OSCAR and CTI models to enhance the feasibility and contextual fit of the resulting OSCAR-S model for older colorectal surgery patients. We documented stakeholder-informed modifications using FRAME to ensure the model preserved core elements while optimizing its delivery. Future research will focus on evaluating the effectiveness of this adapted model on improving clinical outcomes, patient experience, and implementation success.</p> Clinical trial number <p>Not applicable.</p>