Recent unprecedented levels of migration, while adding cultural and linguistic diversity, places increased pressure on host countries to develop strategies for effectively integrating new arrivals into society. This article draws on data from IMMERSE which uses participatory and co-creation methodologies with children, parents, educators and policy-makers to examine and develop key indicators of migrant children’s socio-educational integration. It discusses Irish findings related to language and migrant children’s participation and belonging in school, highlighting children’s concerns over the lack of a diverse language culture and low value placed on preserving heritage language in Ireland and across all six EU partner countries.