Bipolar Disorder (BD) is a complex, cyclical and chronic mental illness where self-tracking is central to self-management. Mobile technology has been leveraged to support self-tracking. Limited research has investigated the patient experience of self-tracking in BD, and it is unclear how the “normative ontology” that is seen in existing self-tracking technology discourses (e.g. the Quantified Self movement) is applicable to the domain of mental health. Combining principles of patient and public involvement (PPI)—a staple research design principle in mental healthcare—with design and HCI-oriented research approaches, we conducted interviews and workshops with people with lived experience of BD to explore reasons and methods for self-tracking, and challenges and opportunities for technology. Our results describe recommendations for the design of self-tracking mental health technology. We also reflect upon the complex role of researchers working at the intersection of emerging mental health technologies, the principles of PPI, UX and HCI research.