This report ‘EIFFEL personas, co-designed scenarios and user requirements’ presents the results of co-design workshops held within each pilot Community of Practice (CoP), to define potential users (stakeholder) of the EIFFEL applications to be developed in each pilot. It should be noted that, currently, each CoP is in the process of being built in congruence with each PILOT’s application development. This report describes the applied methods and the findings, as started from the proposed structure of this task T2.1 ‘Co-design of climate-change related user stories/scenarios and project user requirements’ from the EIFFEL project plan as defined in the Grant Agreement (GA) (Table 1) [1]. Resulting from the workshops, the report describes for each of these potential EIFFEL users (‘EIFFEL Personas’), their user stories as co-designed by the PILOT’s community of practice (‘co-designed scenarios’) and the necessary and optional functionalities for those applications (‘user requirements’). As a project management tool, this report is deliverable D2.1 of the first task (T2.1) of EIFFEL work package 2 on ‘Co-Design of Climate Change applications based on GEOSS’. This deliverable serves as an input for the next task T2.2 ‘Specifications of the EIFFEL tools and Climate change applications’.