Abstract Background Atrial fibrillation (AF) is underdiagnosed and it is estimated that a third of people with AF remain undiagnosed. AF is complex to detect because it can be intermittent and some patients are asymptomatic. When symptoms are present they can be non-specific. In the absence of a screening programme to detect AF it is important to identify ways to improve its detection of AF in order to reduce the risk of AF-related stroke. Purpose We conducted a qualitative study in primary care to explore the patient path to diagnosis of AF and identify ways to improve detection Methods We recruited patients with a recent diagnosis of AF (< 6 months) and interviewed them to understand their path to diagnosis. We interviewed GPs and practice nurses to explore their experience of detecting AF in primary care. The interviews were audio-recorded and transcribed, and the data were analysed using framework analysis. Results Thirty patients and ten primary care clinicians were interviewed. The presence and nature of symptoms experienced by patients and how they interpreted these were significant in the pathways to diagnosis. Patients with acute symptoms presented to A &E and had a quick diagnosis while asymptomatic patients were diagnosed incidentally. Patients with non-specific symptoms generally did not perceive the symptoms as serious, and many delayed seeing a healthcare professional. Their experiences in primary care aligned with findings from interviews with primary care clinicians, who acknowledged AF may not necessarily be the initial suspicion when a patient presents with certain non-specific symptoms. Primary care clinicians described narratives of good practice in the form of opportunistic pulse palpation, as well as challenges of detecting AF in primary care. These included lack of access to 24-hour ambulatory ECG in primary care and limited opportunities to detect AF due to healthcare assistants taking on more responsibilities. Conclusions A number of opportunities to improve the detection of AF can be drawn from these findings. Public education about AF, its signs and symptoms would increase patient knowledge and presentation to healthcare professionals. Standardizing good practice of opportunistic pulse palpation in primary care and training healthcare assistants to perform this is also indicated. Access to 24-hour ambulatory ECG in primary care will reduce delays in diagnosis. Further research on which patients are likely to have undiagnosed AF will facilitate detection in primary care.