The project Step-Change (Science Transformation in EuroPe through Citizens involvement in HeAlth, coNservation and enerGy rEsearch), funded by Horizon 2020 and launched in March 2021, is implementing five Citizen Science Initiatives (CSIs) in the fields of health, energy and environment. The CSIs will tackle the issues of wildlife conservation in Slovenia, non-alcoholic fatty liver disease in the UK, energy communities in Germany, infectious disease outbreak preparedness in Italy, and off-grid renewable energy in agriculture in Uganda. The project will bring novelty in citizen science research while contributing to broader science aspects. The overall objective of Step-Change is to explore the potential of citizen science and to formulate recommendations and instruments for better cementing this approach within research and innovation institutions as well as changing researchers’ mindsets on its value. The project, which aims to make science more socially robust, inclusive, and democratic, will ensure that research institutes make the most of what citizen science has to offer, whilst also identifying, analysing, and limiting the associated risks. Our presentation includes main features of the project, and provides an overview of the multifaceted methodology Step-Change makes use of to foster alignment of CSIs with local contexts, nurture mutual learning, and encourage self-reflection through the means of participatory evaluation exercises. Hence, the presentation provides details about the CSIs but also about the horizontal activities of the project (scoping exercise, mutual learning and training activities, participatory evaluation, stocktaking process), which have been designed to increase the relevance, inclusiveness and sustainability of the initiatives. In this respect, we also focus on the three levels of participation of the CSIs (core team members, citizen scientists and other stakeholders), to explain the mechanisms put in place to boost the level of engagement.