A steady increase in the elderly demographic, particularly those 85+ in age, has given rise to an elevation in global prevalence of neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases, and underscores an urgent need for novel, preventive, and disease-modifying strategies. Marine ecosystems represent a prolific source of bioactive compounds, among which xanthophyll carotenoids—oxygenated derivatives including astaxanthin, fucoxanthin, and canthaxanthin—have emerged as compelling candidates for neuroprotection. These compounds exhibit superior bioavailability and blood-brain barrier permeability compared to hydrocarbon carotenoids, attributed to their polar functional groups. Their potent bioactivity stems from a multifaceted ability to modulate core pathological processes: directly quenching reactive oxygen species, activating the Nrf2-mediated antioxidant response, inhibiting NF-κB-driven neuroinflammation, and interfering with the aggregation of toxic proteins like amyloid-β and α-synuclein. This review evaluates the preclinical and clinical evidence supporting the neuroprotective potential of these three marine xanthophylls. Astaxanthin demonstrates the most robust and extensive evidence base, from cellular models to human cognitive trials. Fucoxanthin shows parallel promise with unique effects on mitochondrial biogenesis, while canthaxanthin remains significantly understudied despite its strong antioxidant profile. We further discuss the translational challenges of bioavailability and formulation, highlighting innovative delivery systems, and propose future research directions to harness these marine-derived compounds for promoting brain health and mitigating age-related cognitive decline.