The workplace has been identified as a pertinent and sustainable setting for providing mental wellbeing support at scale, whilst overcoming the many barriers to accessing timely treatment through traditional healthcare pathways. Given the consequences of delayed treatment on exacerbation of symptoms and costs to both the employer and wider economy, there is a demand for preventative approaches to strengthen individuals’ protective characteristics (e.g., resilience, emotion regulation skills) against poor mental health outcomes. Following on from a feasibility phase, this study will evaluate the efficacy of the revised REST 2.0 intervention, an integrative digital psychological skills training intervention, on improving measures relating to wellbeing and organisational outputs. A multi-centre, mixed-method randomised waitlist controlled trial will be conducted with working individuals recruited from across the Midlands (England), who express an interest in learning coping skills to improve their resilience and wellbeing. Participants will be randomised to the intervention group or waitlist control group with no active treatment. REST 2.0 is an 8-week digital intervention based on integrated, evidence-based psychological approaches. Participants will complete outcome measures at pre-intervention, post-intervention and three months follow-up, with self-efficacy as the primary outcome measure. Secondary outcomes will explore changes (if any) in levels of wellbeing and organisational outputs. A mixed-method participant experiences assessment at post-intervention and follow-up will also explore in more depth usage of newly learnt skills and their impact. Ethical approval has been granted by the University of Warwick Biomedical and Research Ethics Committee and this trial is registered with the Open Science Framework.