STEM integration has often been recommended as a way to support students to develop twenty-first century skills needed to function in the complex modern world. In order for students to experience integration, however, their teachers need support in designing, developing and implementing integrated curricular instruction, which is often at odds with a very subject-focused educational system. This paper reports on the second year of a research study conducted with five secondary science and mathematics teachers, concerned with supporting them to teach explicitly the mathematics components within science lessons, mediated via technology. It outlines how the teachers collaborated with the support of science and mathematics education researchers within a community of practice, named a Teaching and Learning Network (TLN). The network was intended to promote and enhance teacher capacity for the interdisciplinary teaching of mathematics in science in the face of various contextual and other obstacles observed in the first year of the study. This study found that the opportunity to work in a Teaching and Learning Network supported the teachers' ownership of the design of the integrated learning unit, enhanced their content knowledge of mathematics, their use of the data logging technology and their understanding of an inquiry-based pedagogical approach. Participation in the TLN provided teachers with the mechanism to cross the boundaries of the subject disciplines and thereby promoted change in their attitudes, professional knowledge and to some extent, practice.