Marine protected areas (MPAs) are designated ocean regions where human activities are regulated or prohibited to preserve biodiversity, restore fish stocks, and mitigate climate impacts. They range from multiuse to strict no-take zones. Studies show MPAs significantly increase fish biomass and diversity, particularly top predators, creating a spillover effect into adjacent areas. Beyond fish, MPAs also safeguard critical habitats like coral reefs, mangroves, and seagrass meadows, enhancing coastal protection and storing “blue carbon.” However, many MPAs face challenges of underfunding, poor enforcement, and community resistance. Effective MPA networks require robust management, international collaboration, and technological tools like satellite monitoring to ensure long-term ocean health and resilience.