Offshore wind farm assets require regular inspections. Studies and industry experience have highlighted the importance of selecting the appropriate inspection and maintenance (I&M) plan, as it directly impacts the components’ reliability and associated maintenance cost. If inspections are carried out too frequently, reliability and cost will be high and the associated risks will be low. On the contrary, if no or very little inspections are carried out, unexpected failures of the structures could occur. This paper presents a risk-based inspection (RBI) framework for offshore wind farms, building on existing knowledge from other industries; including nuclear, oil & gas, chemical and aerospace. This approach considers the probability, the consequences and the cost of the operational or maintenance activity via a criticality analysis that allows optimal selection and prioritisation of I&M activities. A case study is presented where this framework is implemented on the wind turbines’ transition piece (TP), by investigating information received from design, operational and inspection reports as well as monitoring equipment. Guidelines are also proposed on how to utilise novel monitoring and visual inspection techniques to further improve the implementation of RBI. The results of this paper suggest a less frequent I&M strategy, which could reduce the associated TP inspection costs by up to £0.7m/MW installed and increase the safety of the personnel. The study will be of interest to offshore wind farm developers, operators and maintenance providers, to better prioritise I&M activities and increase the operating revenue of their assets.