ABSTRACT Whilst there is a body of emerging literature related to science education for children aged 3 years and above, less is known about educators’ beliefs when planning for the teaching of science concepts to infants and toddlers in group settings. This paper discusses how educators working with children under 18 months of age talk about and plan for the teaching of science concepts. We undertook an educational experiment with 6 educators and 11 infants aged 1.1–2.0 years (mean 1.6 years). An analysis of the digital data of 18.1 h (5.2 h of adult-researcher data; 12.9 h of observations) revealed both roadblocks and contradictions in educators’ beliefs and practices when planning for infant and toddler learning of science concepts. Initial contradictions for educators include focusing on activities not concepts, following interests and not introducing science content, and a belief associated with developmental restrictions regarding if science concepts and science resources are relevant/safe for this developmental period. These were genuine blocks in shifting educators’ beliefs towards planning for the learning of science concepts. We found under the conditions of an intervention, these roadblocks were resolved, giving more opportunities for infant-toddler engagement in science learning.