This phenomenological research was designed to learn and understand the transitioning experience of high school teachers moving from traditional face-to-face instruction to online instruction by answering the question: What are lived experiences of high school teachers who teach online? The researcher searched for teachers‘ personal reflective knowledge shaped and reshaped through their experiences through the following guiding research questions: 1. How do high school teachers describe their experience transitioning from traditional face-to-face instruction to online instruction? 2. What are the unique needs and challenges of online high school teachers as expressed by the teachers themselves? 3. What teaching strategies do online high school teachers find most effective in their online teaching experience? 4. How do high school teachers describe how they adapted their teaching to online instruction? 5. What value do online high school teachers assign to this research? A study website was used to elicit responses to a study questionnaire, and a face-to-face exit interview was employed to provide a layered approach to the data collection. This allowed for a comprehensive excavation of participants‘ narratives of their experiences. Study participants were online high school teachers from the school system‘s online high school program where the researcher teaches, who have taught an online course for at least one semester, with experiences relating to the phenomenon. An analysis of the data revealed four dominant themes: communication, teacher roles, technology, and professional development and mentorships. Participants reported many challenges and a need for ongoing professional development directed at keeping pace with emerging technologies, and strategies to create an online community that uses best practices of an online teaching and learning environment.