The South African Physical Sciences Curriculum and Assessment Policy Statement (CAPS) requires learners to develop science inquiry skills, including Integrated Science Inquiry Skills (ISIS). However, the performance of learners in assessment tasks related to ISIS has been consistently poor over several years. The use of ineffective pedagogical methods to develop practical skills could partly account for this poor performance. This study compared the effectiveness of individual and group practical investigations in developing ISIS in learners. The study involved 319 purposively selected Grade 11 Physical Sciences learners in Limpopo Province, South Africa. A mixed-method approach was used to collect data. Pre- and post-tests, and practical reports were used to assess learners’ competence in ISIS, while a questionnaire provided information about their opinions regarding the investigation methods used. A comparison of the performance of the two classes of learners showed no significant difference in their overall competence in ISIS. Qualitative analysis of the practical reports and learners’ opinions revealed some discrepancies between the two investigation classes. The results suggest that the two approaches to practical investigations are approximately equally effective in developing learners’ overall ISIS.