Integration of computational thinking and programming into science, technology, engineering, and math (STEM) classes is needed to promote students' learning of twenty-first century skills. Yet, teachers are not equipped to achieve this integration successfully as teacher education curricula do not generally align with this need. With the COVID-19 outbreak, curricula also need to be adapted for online environments. This qualitative study presents the redesign of an educational technology course that introduces programming and computational thinking to STEM preservice teachers for online settings, and explores learning experiences of preservice teachers, in terms of how they combine technological knowledge with pedagogy and content. Data were collected from course artifacts, such as reading responses, coding challenges, and lesson designs and implementations. The findings showed the online course design was helpful in enhancing preservice STEM teachers' pedagogical approaches of how to teach computational thinking and programming. Offering hands-on coding practices in the course allowed preservice teachers to improve their technological knowledge (programming), and they were able to integrate their technological pedagogical knowledge into their content area and design meaningful lessons. The study offers implications for design of online teacher education courses that promote preservice teachers' technological pedagogical content knowledge for computational thinking and programming.