Many programming environments are promoted as tools for teaching Computational Thinking (CT) and coding skills to young children, particularly those in preschool. However, their effectiveness is still in the early stages. In a study conducted over three weeks, a teaching intervention was used to explore how ScratchJr can improve CT and basic coding skills in a group of preschoolers (N = 34, aged 4–6). The mean pretest performance of the control group (M = 7.07, SD = 2.58) was significantly higher than that of the test group (M = 5.35, SD = 1.58), t(22.64) = 2.23, p = .036. Nevertheless, careful examination of the data indicates a statistically significant improvement in preschoolers exposed to the ScratchJr educational intervention. The findings provide evidence for the efficacy of the programming environment in fostering CT and coding abilities among young children in preschool. Both teaching approaches equivalently foster the fundamental coding concepts of control structures and modularity. The experimental cohort performs statistically significantly better than the control group in understanding the powerful ideas of algorithms, hardware/, and representation. In contrast, the control group outperforms the test group in understanding the debugging concept. The results strongly support the effectiveness of the programming environment ScratchJr, highlighting its ability to develop CT and coding skills in preschoolers.