With an area 20 times that of the island itself, Jersey’s marine environment is a vital resource. Incredibly diverse, with over 3,000 known animal and plant species, its range of habitats provide essential services to the Island including food, climate regulation, nutrient cycling, coastline protection, recreation and wellbeing. In 2022, the Government of Jersey committed to developing Jersey’s first Marine Spatial Plan (MSP) with the aim of balancing the different uses of the marine environment. The MSP includes a commitment to extend Jersey’s Marine Protected Area (MPA) network by 2025. Despite an existing network of MPAs, 93 per cent of Jersey’s seabed remains unprotected and at risk from damaging activities such as bottom-towed fishing and infrastructure development. With global targets to protect 30 per cent of the ocean by 2030 (a target Jersey is a signatory to via the UK), the MSP provides a unique opportunity to secure significant protection of Jersey’s marine environment while safeguarding and maximizing the services it provides to the Island. This report outlines the findings of an Ecosystem Service Valuation model completed by Blue Marine Foundation (Blue Marine) and the New Economics Foundation (NEF) to establish the ecosystem services (ES) provided by Jersey’s marine environment to the Island. The model uses a benefit transfer approach to estimate the ecosystem service value for ten scenarios for the extension of Jersey’s MPAs through the MSP process. Understanding Jersey’s marine resources is essential in the development of an MSP for the island. This report highlights that higher protection levels through a proposed marine park could deliver an extensive MPA network, covering habitats essential for biodiversity, carbon sequestration, sustaining fisheries and the wellbeing of Jersey’s population.