The COVID-19 pandemic profoundly altered socio-economic activities, human behaviors, and crime patterns. However, less is known about how the pandemic and associated restrictions affected cyber-enabled and traditional fraud. Here, we conducted a retrospective analysis using police-recorded crime data in the UK to examine the impact of COVID-19 restrictions and changes in human activity on fraud. Results indicate that following the onset of the lockdown, the number of recorded fraud cases increased by 28.5%, contrasting with traditional property crimes, which dropped by 28.1%. However, the lockdown did not have a significant impact on the long-term trend of fraud. With the lifting of restrictions, fraud gradually regressed to levels approaching those before the pandemic. By inspecting the effects of different government responses and changes in population mobility on various types of fraud, we found that more stringent restrictions were associated with larger increases in most types of cyber-enabled fraud, except for those that rely on offline activities, whereas the impact on traditional fraud was mixed and contingent upon specific opportunity structures. These findings overall align with the assumptions of routine activity theory and provide clear support for its applicability in fraud and cybercrime.