Background: Early childhood education and care (ECEC) services have the potential to influence or disrupt sleep patterns given that ECEC attendance coincides with the normative transition towards napping cessation. Objective: In light of the evidence that sleep patterns in early childhood are foundational to lifelong health, this study investigated parent-educator communication about children's 24-h sleep cycles. Communication is critical in ensuring regularity and responsiveness to children's sleep behaviours, yet knowledge about if and how this happens is limited. We sought to address this gap. Method: This study draws upon survey data, both numeric and text, from 116 parents and 39 educators across 25 ECEC services in Brisbane, Australia. The type and regularity of communication strategies between ECEC educators and parents were analysed to establish frequency and demographic patterning. Qualitative analyses investigated the content of sleep-related communication between educators and parents. Results: Most educators and parents reported discussing children's sleep through in-person communication at pick-up and drop-off times. Qualitative analysis of the content of parent-educator communication identified three key themes: sleep quantity, quality and practices. Communication focused primarily on the quantity of children's sleep while attending ECEC settings, and communication about sleep quality and home practices were less frequent. Educators communicated more sleep-related information with parents than parents did with educators. Conclusions: This study highlights the need for frequent, bi-directional parent-educator communication. Providing practices which support regularity of sleep across home and ECEC settings and responding to the developmental transition toward napping cessation promotes children's sleep health.