As the employment landscape for Early-Career Researchers (ECRs) is becoming increasingly intersectoral, international, and interdisciplinary, it is important that doctoral programs include training in soft and hard skills that are not only fundamental for research, but are also transferable to other careers. These transferable skills can increase ECRs’ employability, allowing them to pursue different career paths and broaden their options in the academic, governmental, and private sectors. Among others, transferable skills related to Open Science are becoming increasingly important, and they can be acquired with doctoral training. However, as the EOSC Executive Board Skills and Training Group pointed out, several issues still exist. These include a lack of Open Science expertise (particularly in relation to Open Data), varying levels of digital literacy, inadequate media and communication skills, and a lack of centralization of learning and training resources. On the other hand, measuring researchers’ skills and competences is a key first step for the European Commission towards addressing the precarity of ERCs and reducing brain drain. We have reviewed the curricula of two course providers in Open Science, FOSTER and the Open Science MOOC, and have identified a list of transferable skills, classifying them on the basis of learning outcome. Through this classification, we have found that a diverse array of transferable skills are crucial to Open Science education. We foresee a key role of Open Science training and its derived skills in empowering researchers for their career development and assessment.