BACKGROUND: Prehabilitation optimizes colorectal cancer patients' health during the preoperative waiting period, by increasing functional capacity, reducing postoperative complications, and speeding recovery. However, challenges in implementation include patients' willingness to attend multiple hospital visits, and hospitals needing trained personnel, facilities, and financial resources. An app-based prehabilitation program could address these issues by allowing patients to participate from home with remote support from healthcare professionals. OBJECTIVE: To develop and evaluate the feasibility of a digital application to offer multimodal home-based prehabilitation for older patients undergoing surgery for colorectal cancer. MATERIALS AND METHODS: This single-center prospective cohort study at Northwest Clinics (Alkmaar and Den Helder, The Netherlands) included patients scheduled for elective surgery for the curative treatment of colorectal cancer. The Patient Journey App was used to deliver prehabilitation. The primary outcome was the number of patients who downloaded and activated the app. Secondary outcomes included usage information, videos viewed, questionnaires answered, and signals triggered. RESULTS: Ninety-seven patients were included in the study (age 72.1 [SD 0.8], 62.9% male). All patients used the app daily for a median of 29 days (IQR 23-28). Exercise videos were viewed most. Ninety-five patients activated daily exercise and protein shake reminders. Patients provided 1367 answers, triggering 79 signals related to smoking cessation, nutrition, and exercise. Response rates to in-app questionnaires were high, up to 90.5%. CONCLUSIONS: Home-based prehabilitation via an app for older colorectal cancer surgery patients is feasible. Given the effectiveness of prehabilitation programs, the scarcity of healthcare professionals, and patients' reluctance for frequent in-person visits, home-based prehabilitation programs via an app could become a valuable added modality for offering these programs. TRIAL REGISTRATION: 2020.0600 (VU University Medical Center).