<p class="Default">The objective of this research was to enhance two case studies of pre-service science teachers’ practice according to SSI-based teaching through collaborative action research. The case study participants had taken a field experience course in the universities in Bangkok in the academic year 2014. The researcher gathered data from classroom observation, students’ journal entries, and student artifacts. In addition, they were asked to write journal entries about their practices. Moreover, informal interviews were used for clarification. These collected data were analyzed using within-case and cross-case analyses. The findings showed that both case studies developed grade 10 students’ argumentation skills through SSI-based teaching in natural resource unit with 4 stages of teaching: issue stage; exploration stage; argument stage; and decision making stage for promoting students’ argumentation. Based on the collaborative action research, the participants changed their teaching to engage students with SSI; increasing facilitating of students’ group working in order to get more essential information; using role play to promote the effective students’ argumentation; and providing enough time for reviewing data to better support decision making. <strong></strong></p> <p class="Default"> </p> <p><strong>Keywords: </strong>Pre-service science teachers, Socioscientific issue-based teaching, Collaborative action research</p>