INTRODUCTION: Children's skin is particularly susceptible to the carcinogenic effects of ultraviolet radiation. Young children are dependent on sun protection measures taken by parents and other caregivers. OBJECTIVES: The aim of the study is to evaluate parental sun protection behavior and sun protection measures at preschool at two points in time (2010/11 and 2018/19) in Bavaria and to test for a secular trend. METHODS: Two cross-sectional surveys were carried out. For each survey, more than 4,000 parents of preschoolers completed a self-administered questionnaire about parental sun protection behavior and sun protection measures at preschool. To identify possible associations between parental sun protection behavior and sociodemographic characteristics, logistic regression analysis was carried out. RESULTS: In the survey of 2018/19, six out of eight sun protection measures are adequately applied by over two-thirds of the parents. Two out of eight sun protection measures are adequately applied by less than one-third of the parents. Those two measures are aligning sun protection to actual UV index and preschoolers wearing sunglasses. The comparison of the study population of the survey of 2010/11 and of 2018/19 shows an improvement in parental sun protection behavior for seven out of eight sun protection measures. In both surveys more than 80% of parents state that preschool staff ensures preschoolers wear sun hats and sunscreen outside on sunny days. CONCLUSIONS: Future campaigns should focus on the use of sunglasses and promote the UV index, as these sun protection measures are used very little.