The coronavirus pandemic (COVID-19) will undoubtedly have psychological impacts for healthcare workers, which could be sustained; frontline workers will be particularly at risk. Actions are needed to mitigate the impacts of COVID-19 on mental health by protecting and promoting the psychological wellbeing of healthcare workers during and after the outbreak. We developed and evaluated a digital learning package using Agile methodology within the first three weeks of UK outbreak. This e-package includes evidence-based guidance, support and signposting relating to psychological wellbeing for all UK healthcare employees. A three-step rapid development process included public involvement activities (PPIs) (STEP 1), content and technical development with iterative peer review (STEP 2), and delivery and evaluation (STEP 3). The package outlines the actions that team leaders can take to provide psychologically safe spaces for staff, together with guidance on communication and reducing social stigma, peer and family support, signposting others through psychological first aid (PFA), self-care strategies (e.g., rest, work breaks, sleep, shift work, fatigue, healthy lifestyle behaviours), and managing emotions (e.g., moral injury, coping, guilt, grief, fear, anxiety, depression, preventing burnout and psychological trauma). The e-package includes advice from experts in mental wellbeing as well as those with direct pandemic experiences from the frontline, as well as signposting to public mental health guidance. Rapid delivery in STEP 3 was achieved via direct emails through professional networks and social media. Evaluation included assessment of fidelity and implementation qualities. Essential content was identified through PPIs (n = 97) and peer review (n = 10) in STEPS 1 and 2. The most important messages to convey were deemed to be normalisation of psychological responses during a crisis, and encouragement of self-care and help-seeking behaviour. Within 7 days of completion, the package had been accessed 17,633 times, and healthcare providers had confirmed immediate adoption within their health and wellbeing provisions. Evaluation (STEP 3, n = 55) indicated high user satisfaction with content, usability and utility. Assessment of implementation qualities indicated that the package was perceived to be usable, practical, low cost and low burden. Our digital support package on 'psychological wellbeing for healthcare workers' is free to use, has been positively evaluated and was highly accessed within one week of release. It is available here: Supplementary Materials. This package was deemed to be appropriate, meaningful and useful for the needs of UK healthcare workers. We recommend provision of this e-package to healthcare workers alongside wider strategies to support their psychological wellbeing during and after the COVID-19 pandemic.