Digital cognitive behavioural therapy for insomnia has been developed to increase capacity and scalability for patients with insomnia, but implementation in primary care remains limited. The aim of the trial was to evaluate the implementation of digital insomnia therapy into primary care practice for patients with insomnia. We conducted a single-arm feasibility trial of digital behavioural therapy for insomnia (SleepFix) providing sleep restriction therapy with insomnia patients in primary care. Healthcare professionals (comprising General Practitioners, community pharmacists and nurses) were enrolled into the trial and, when deemed clinically appropriate, prescribed SleepFix to patients with insomnia. The primary outcome was uptake assessed by the number of downloads of SleepFix. Interviews with primary care healthcare professionals explored their attitudes towards implementing/using insomnia digital therapeutics in clinical practice, and patients about their experiences with SleepFix. Insomnia symptoms, mood and sleep quality were measured before and after the trial. This trial was prospectively registered (ACTRN12620000055909). Thirty healthcare professionals and 105 patients were enrolled into the trial. Fourteen healthcare professionals administered at least one insomnia digital therapeutic prescription between November 2021 and March 2022. Fifty patients downloaded and used SleepFix (47.6% uptake). In post-trial interviews, healthcare professionals felt they could incorporate digital sleep health into clinical practice and patients found SleepFix acceptable. There were significant improvements in insomnia symptoms, mood and sleep quality at week 6 (all p < 0.05). This trial shows a real-world implementation of a digital insomnia therapy into primary care that could provide a framework for prescribing digital sleep interventions.