Researchers have argued that integrating early algebra into elementary grades will better prepare students for algebra. However, currently little research exists to guide teacher preparation programs on how to prepare prospective elementary teachers to teach early algebra. This study examines the insights and challenges that prospective teachers experience when exploring early algebraic reasoning. Results from this study showed that developing informal representations for variables and unknowns and learning about the two interpretations of the equal sign were meaningful new insights for the prospective teachers. However, the prospective teachers found it a conceptual challenge to identify the relationships contained in algebraic expressions, to distinguish between unknowns and variables, to bracket their knowledge of formal algebra and to represent subtraction from unknowns or variables. These findings suggest that exploring early algebra is non-trivial for elementary prospective teachers and likely necessary to adequately prepare them to teach early algebra.