This review examines the growing concern over persistent, non-biodegradable micro- and nanopollutants in marine environments, driven largely by industrial activities, particularly manufacturing processes involving micro- and nanoparticles. Global oceans are increasingly burdened by complex mixtures of heavy metals, engineered nanomaterials (ENPs), and micro- to nanoplastics, all of which threaten ecosystem integrity and seafood safety. Heavy metals accumulate in sediments and marine organisms, enabling biomagnification through the food web. ENPs, with their nanoscale dimensions and unique physicochemical properties, are difficult to remove using conventional treatment methods. Micro- and nanoplastics worsen the problem by acting as vectors for toxic substances, enhancing their transport and bioavailability across trophic levels. Mitigating these pollutants demands integrated solutions. Advanced separation technologies, such as membrane filtration (MF, UF, NF), achieve high nanoparticle removal efficiency, while adsorption-based materials like MOFs and COFs effectively capture plastics and associated contaminants. Biological strategies, including enzymatic degradation by marine algae and their microbial consortia, offer sustainable, low-impact alternatives for long-term management. The combined application of physical, chemical, and biological interventions provides a multi-barrier defense, improving pollutant removal, reducing ecological risks, and supporting the restoration of marine ecosystem resilience.