Background <p>Insomnia symptoms during the perinatal period are prevalent and may contribute to negative mental health and birthing outcomes. Cognitive Behavioural Therapy for Insomnia (CBT-I) is a non-pharmacological therapy efficacious in the treatment of insomnia. Previous studies have shown the effectiveness of digital CBT-I during the perinatal period. However, to date, our understanding of whether this treatment can be effectively implemented in community perinatal care is limited.</p> Methods <p>In this two-arm hybrid effectiveness-implementation type 1 randomised controlled trial (RCT), eligible pregnant individuals with self-reported insomnia symptoms (Insomnia Severity Index &gt; 7) will be randomised to either the CBT-I intervention (Healthy Sleep Program) or active control (sleep hygiene education). The primary outcome is maternal insomnia symptom severity at (i) one pregnancy endpoint and (ii) averaged across three times post birth for the postpartum endpoint. An economic evaluation will assess cost-effectiveness. Barriers and enablers to sustained implementation will be explored using the Theoretical Domains Framework and the Practical Robust Implementation and Sustainability Model.</p> Discussion <p>This study will offer an understanding of the effectiveness, cost-effectiveness, and sustained implementation potential of a digital sleep health program in perinatal care. These outcomes will provide empirical evidence to inform broader implementation of a scalable sleep program to improve insomnia symptoms in perinatal populations.</p> Trial registration <p>Australian New Zealand Clinical Trials Registry ACTRN12622000940774. Registered on 1 July 2022.</p>