Background and context: Transfer is a process where students apply their learning to different contexts. This process includes using their knowledge to solve problems with similar complexity, and in new contexts. In the context of programming, transfer also includes being able to understand and use different programming languages. Objective: This study explores: (a) student ability to transfer from a block-based programming language into another block-based programming language; (b) student ability to transfer from a block-based programming language to a text-based programming language; (c) student ability to transfer their learning within the same programming language; and (d) the difficulties students had to transfer in these contexts. Method: A group of students participating in a program called Coding For Kids explained three different programs in different programming languages during an interview protocol. The students used the programming language MakeCode, and worked on transfer activities in Scratch and Python. Findings: The results suggest that while most students are able to transfer between block-based programming languages, most of them struggle to explain a program in a text-based programming language, and to solve a new coding challenge. Implications: Instructional designers should consider different strategies to facilitate student transfer into professional programming languages, which is particularly difficult for non-English speakers.