This study aimed to understand teachers' classroom practices using computer-based simulations (CBS) when teaching electrolysis. The study was framed by the Consensus Model of Pedagogical Content Knowledge. Convenience and purposive sampling were used to select three experienced chemistry teachers from three schools in Eswatini (Swaziland). Semi-structured interviews, questionnaires and classroom observations were used in the data collection. The data were analysed using qualitative content analysis in terms of six emergent themes. The findings of this study reveal how the teachers' views and knowledge about CBS and electrolysis relate to the way they integrate CBS into their lessons while teaching this topic. The teachers all believed that CBS enhances learners' understanding of electrolysis because it enables learners to visualise abstract processes, and because the simulations raise learners' interest and enhance critical thinking. Two of the teachers valued learners' involvement in the manipulation of the CBS, while the remaining teacher believed that it was adequate for learners to 'see' the movement of ions and electrons. During classroom discussions following the simulations, the teachers sometimes displayed poor content knowledge, thus reducing the value of the learning experience. All of the teachers were concerned that the shortage of equipment, large class sizes and the poor socio-economic background of the learners may affect the effective use of CBS. Although the schools participating in this study had computers, they were reserved for use by the ICT departments, adding to the obstacles faced by the teachers. It is recommended that teachers are made familiar with the pedagogy of using CBS, and that teachers' content knowledge should be prioritised during their training to enhance the effective use of CBS.