Recent analysis of European onshore wind turbine reliability data has shown that whilst wind turbine mechanical subassemblies tend to have relatively low failure rates but long downtimes, electrical and electronic subassemblies have relatively high failure rates and short downtimes. For onshore wind turbines the higher failure rates of electrical and electronic subassemblies can be managed by a maintenance regime that provides regular and frequent attendance to wind turbine sites. This regime will be costly or impossible to sustain in more remote onshore or offshore wind farm sites. This paper gathers data supporting the contention that electrical and electronic subassembly failure modes are a significant contributor to wind turbine unreliability, identifying some of their root causes, showing how they will play a more significant part in the availability of offshore wind turbines. The paper concludes by showing how more can be learnt to eliminate or mitigate some of these electrical and electronic subassembly failure modes.