It is critical to support children’s science learning starting from infancy. However, there is little research investigating introducing science to children under three years old. The current study addressed this gap by examining the effectiveness of setting up an Inquiry-Based Science Table(IBST) in a toddler classroom. A classroom in Hong Kong with 18 toddlers and two teachers was selected as the implementation site. A qualitative approach was used to collect data. Toddlers’ interaction with the IBST was observed and recorded using the Science Behaviour Checklist. Two class teachers were invited for semi-structured interviews about their views on science teaching and the effectiveness of the IBST. The results indicated that the frequency, variety and complexity of toddlers’ science behaviours increased after the IBST was placed. The adult’s mediating role in supporting toddlers’ science learning was highlighted, while concerns and challenges of implementing science teaching to toddlers were also presented and discussed. The study suggested that more rigorous research with larger sample sizes should be conducted to investigate effective science instruction for children under three and professional training on science teaching should be provided to teachers working with infants and toddlers.