One of the prerequisites for chemistry teacher candidates is to demonstrate certain laboratory skills. This article aims to determine and discuss the competencies of pre-service chemistry teachers in a chemistry laboratory context working with solution chemistry content. The participants in this study consisted of a group of pre-service chemistry teachers in the first to fifth years of a chemistry teacher education program. The participants were given individual tasks of preparing solutions of a certain concentration. The tasks included two steps: calculation and application. The participants were also observed in terms of the degree to which they followed the laboratory safety rules. Overall, the pre-service teachers made numerous errors in calculating the correct amounts of a substance and preparing a solution, as well as obeying the safety rules. Interestingly, the participants' laboratory competencies showed a trend along their grade levels; namely, a slight increase and then a sharp decrease in their solution preparation knowledge and skills that could be associated with retention loss or decay over time in the absence of rehearsal and/or ill-encoding. These results may contribute to the discussion on virtual and physical laboratories in chemistry education.