Despite increasing data on young children's patterning skills and evidence of a link between early pattern knowledge and later mathematics performance, little is known about the strategies children use to solve patterning tasks. This mixed-methods study examined 3- to 5-year-old children's informal strategies when solving eight patterning tasks with three different repeating patterns. In a sequential qualitative-quantitative design, patterning strategies were first longitudinally observed and categorized into five hierarchically ordered categories (n = 6), and then cross-sectionally tested and quantified (n = 174). Results show that young children use various different patterning strategies, and that both patterning strategies and skills organically develop between the age of three and five. However, despite high correct solution rates, the 5-year olds' strategies still reflect little attention to the patterns' structure, suggesting that a pattern and structure based instruction is needed to help young children abstract the unit of repeat.