With only a few wave and tidal devices in the water and no long-term post-installation datasets available, there continue to be uncertainties around risks to marine animals and habitats from the deployment and operation of marine renewable energy (MRE) systems. Based on these uncertainties and lack of familiarity with MRE devices, regulators and stakeholders continue to perceive a wide array of potential environmental interactions as risky and require considerable monitoring in order to permit or license a project. The MRE industry is struggling with the high cost of baseline assessments and post-installation monitoring, as well as long timelines for obtaining permits, leading to uncertainty and risk for financing projects. In order to move towards commercial development of MRE projects, there is a need to distinguish among environmental risks and to manage them. Risks due to uncertainty can likely be reduced and perhaps retired with the collection of additional data, while actual risks to animals and habitats can be avoided or mitigated. Interactions that continue to be uncertain, yet are perceived to be potentially risky, can become the focus of proportional monitoring programs, with the goal of better understanding and minimizing those risks.