In Australia, early childhood education takes a play-based approach to supporting children's engagement with mathematical ideas and numeracy development. To assist preschool teachers' implementation of the outcomes in the national Early Years Learning Framework for Australia, the Northern Territory (NT, Australia) has introduced the NT Preschool Curriculum. The NT Preschool Maths Games, a suite of play-based games underpinned by mathematical concepts, was developed to support the enactment of this curriculum. Here, we explore the impact of attending a preschool classroom in which the NT Preschool Maths Games is being implemented, on child learning outcomes in a pre–post intervention design. Children were assessed in regard to their number naming, counting, and Applied Problems skills. After the baseline assessments, the teachers in the intervention rooms were equipped with the NT Preschool Maths Games and attended a one-day workshop on how to use them. Compared with children in the delayed intervention group, children in the intervention group showed statistically greater gains in their mathematical competencies in a post intervention assessment. This suggests that the NT Preschool Maths Games may support the enhancement of child learning outcomes.