Findings from child development research support inclusive practice in early childhood education to enable full participation of all children in learning activities and build their core capabilities for life. However, the implementation of inclusive practices in early childhood is often constrained by boundary-crossing barriers. This paper reports a quantitative study that investigated and analysed the inclusive practice experiences of 344 pre-school teachers across the six regions of Thailand. The study identified positive experiences of inclusive practices linked to effective collaboration with minimal barriers related to time, increased workload and lack of resources to help teachers cater to the needs of all children. The findings offer direction for developing teachers as leaders to work effectively across professional boundaries so that Thailand can achieve the goals of inclusive education for all children.