A new report by the Platform for International Cooperation on Undocumented Migrants (PICUM) outlines ways for advocates to engage with legal systems on national and international levels. Drawing on discussions among representatives from key monitoring bodies, legal experts, and service providers at PICUM’s Annual Workshop, the report is a guide for practitioners that can be used to enforce the fundamental rights of undocumented migrants through mechanisms at the national level and in the EU, the Council of Europe, and the UN.