This article examines the implementation of new special education legislation in Finland among students with significant disabilities. The data consist of a nationwide survey and field observations. In the analysis, a policy implementation framework is utilized as a theoretical lens. The findings suggest that schools and municipalities that had participated in long-term development projects had more capacity and willingness to reform special education practices substantially, suggesting that learning in one policy area can transfer to other domains across multiple levels of national and local governments. The key findings highlight the significance of professional trust as a policy instrument in implementation.