Background: Most people with a stoma worry about leakage, and a quarter experience leakage of stomal effluent outside the baseplate on a monthly basis. Leakage has additional physical and psychosocial consequences, for instance, peristomal skin complications, feeling unable to cope, and self-isolation. Method: An interventional, single-arm, multi-centre study was undertaken in the United Kingdom to evaluate a novel digital leakage notification system for ostomy care, including a support service (=test product) for 12 weeks in patients with a recent stoma formation (≤9 months). Patients completed questionnaires at baseline and after 4, 6, 8, 10, and 12 weeks, evaluating leakage episodes, Ostomy Leak Impact (tool containing three domains), and patient self-management (by PAM-13). Additionally, mental well-being (by WHO-5) and health-related quality of life (QoL) (by EQ-5D-5L) were assessed. Outcomes between baseline and final evaluation were compared by generalised linear and linear mixed models. Results: 92 patients (ITT population) with a mean age of 49.4 years (range 18–81 years) were recruited. Of these, 80% had an ileostomy, and 53% were female. After 12 weeks of using the test product, a significant decrease in mean episodes of leakage outside the baseplate (1.57 versus 0.93, p < 0.046) was observed. Ostomy Leak Impact scores improved across all three domains (p < 0.001), indicating less embarrassment, increased engagement in social activities, and increased control. Patient self-management also improved significantly (PAM-13 score: ∆6.6, p < 0.001), as did the WHO-5 well-being index (∆8.0, p < 0.001). Lastly, EQ-5D-5L profile scores tended to improve (p = 0.075). Conclusions: A new digital leakage notification system demonstrated strong improvements to patients’ stoma self-care, mental well-being, and QoL. Registration number on ClinicalTrials.gov: NCT05135754.