Transition of the global energy sector is in progress. The share of renewable energies has increased over time and achieved 36.6% of global electricity capacity in 2020. Marine Renewable Energy plays a substantial role in this transition. However, while marine renewable energy will contribute to less GHG emissions, and thus enhance compliance with the Paris Agreement, there are concerns over potential impacts marine renewable energy installations may have on biodiversity. Such impacts include, among others, habitat loss, collision risks, noise and electromagnetic fields. This paper addresses these issues from the perspective of international environmental law, illustrating how potentially conflicting objectives (mitigating greenhouse gas emissions and preserving biodiversity) can be accommodated. This requires a discussion of broader concepts such as no harm and precautionary action as well as detailed rules extending from marine protected areas to the discussion of specific treaty issues, even public participation, including participation of indigenous peoples. The paper aims at illustrating the ability of international law to ensure not just an environmentally sound but a biodiversity-compatible transition towards marine renewable energy.