This article compares the immersion-education systems in Brittany and Wales. The number of Welsh speakers is growing thanks to its well-developed immersion-education system. Brittany has a much less well-developed system and the number of Breton speakers is falling dramatically. Urgent action is needed if Breton is to survive. Using an approach based loosely on 'comparative history as a comparison of contrasts', the paper examines differences in political support for immersion education between the two regions. It considers the impact of this support on planning strategies and mechanisms and considers how a range of pedagogical factors including age of exposure, language-use in the classroom and teacher training are tackled in the two contexts. It finds that the Welsh system enjoys far greater political support than that of Brittany because control of the education system is in the hands of a devolved regional authority which fully supports the regional language. The situation may be about to improve for Breton owing to the publication of a recent circular authorising full-immersion education within the state-education system for the first time. The paper recommends close collaboration between the two regions moving forward in an attempt to save Breton from extinction.