Several nations around the world start to consider marine renewable energy (MRE) to be an alternative energy to sustainable development. The utilisation of the ocean includes common interests for food provision, artisanal fishing opportunity, natural products, carbon storage, coastal protection, tourism and recreation, coastal livelihoods and economies, sense of place, clean waters and biodiversity. An index is required to relate the marine renewable energy industry to ocean healthiness quantitatively. The Ocean Health Index (OHI) recently published in Nature measures the healthiness of the ocean within 171 Exclusive Economic Zones (EEZs). This study identified several data gaps and suggests improvements for the treatment of MRE in OHI calculations. It is suggested to include MRE effects under pressure (pi) or resilience (ri) variables based on the MRE technology type, stage of operation and its effects on OHI goals. The study suggests the OHI may be a suitable indicator to monitor MRE developments after fully including the components of MRE. Policy makers can use the improved OHI to balance the various multiple-competing activities in maritime spatial planning.