Work is a key element in the UN Sustainable Development Goals (SDGs). Crowdwork is a new way of working defined as a paid, digital platform-enabled form of work based on crowdsourcing model. Previous research on crowdwork narrowly considered its direct and immediate economic impact on individual workers overlooking its broader sustainable impact. This study goes a step further and adopts a wider sustainable development approach to examine the relationship between crowdwork and the sustainable development of the workers involved. It questions whether crowdwork contributes to the sustainable development of workers, and if so, how? An inductive research approach is adopted, and rich qualitative data was collected benefiting from a unique access to crowdworkers. The study reveals that crowdworkers develop three types of skills in the process of crowdwork namely; domain, platform and business skills. It highlights that these developed knowledge and skills are transferred from crowdworkers to other workers and other work settings. Furthermore, it traces and identifies the process through which crowdworkers develop and transfer these skills and knowledge and categorises it into three stages of Reactive Exploitation, Proactive Expansion, and Transfer. The study concludes that this process contributes to a more sustainable human resource development not only for the crowdworkers involved but for others as well contributing to the sustainable social and economic development.