In recent years, educational robotics has become an increasingly popular research area. However, limited studies have focused on differentiated learning outcomes based on type of programming interface. This study aims to explore how successfully young children master foundational programming concepts based on the robotics user interface (tangible, graphical, hybrid) taught in their curriculum. Thirty-five Kindergarten students participated in a 9-week robotics curriculum using the LEGO WeDo robotics construction kit and the Creative Hybrid Environment for Robotic Programming (CHERP) programming language. A mixed methods data collection approach was employed, including qualitative observational data from the classrooms, as well as quantitative mid- and post-test assessments of students' programming knowledge using CHERP. The findings show little association between user interface and programming comprehension, although there may be an order-affect when introducing user interfaces. Implications for best practices when introducing programming in early childhood settings are discussed.