Sustainable development (SD) is an approach that aims to meet the needs of the present generation without compromising the ability of future generations to meet their own needs. Education for sustainable development (ESD) is a key component in achieving this goal, as it equips young people with the knowledge, skills, and values needed to make sustainable decisions. This study investigated how preschool teachers in Saudi Arabia understood (SD) and the state of (ESD) practices. A survey was used to collect data from 230 Saudi preschool teachers. The findings revealed that 90% of teachers lacked awareness regarding SD. The overall evaluation of ESD practices among participants indicated a weak subpar status, with an average score of 2.49 out of 4. Notably, in ascending order, the following three dimensions had weak mean scores: the content aspect (2.38) had the lowest score, followed by the practice aspect (2.54) and the competencies aspect (2.58). Meanwhile, the values aspect (2.63) had an average outcome. Analysing the mean scores of ESD practices based on teachers’ qualifications and school types revealed significant differences, although no variations were observed based on experience. The primary obstacle to ESD implementation in pre-schools was the lack of awareness regarding SD/ESD. The study underscores the significance of expanding teacher training to promote ESD effectively in pre-school settings. The results highlight the need for professional development opportunities to improve ESD implementation in classrooms, educate Saudi preschool teachers about SD, and create instructional materials that align with the principles of ESD.