Citizen science is a flexible concept which can be adapted and applied within diverse situations and disciplines. The statements contained in the '10 Principles' document were developed by the ‘Sharing best practice and building capacity’ working group of the European Citizen Science Association (ECSA), led by the Natural History Museum London with input from many members of the Association, to set out some of the key principles which as a community we believe underlie good practice in citizen science. The official repository for this work has now moved to Zenodo: https://zenodo.org/record/5127534#.YPrkNEBCRhE Multiple language versions of The Ten Principles of Citizen Science can be found there.