The pervasive misuse of antibiotics has precipitated a global crisis of antimicrobial resistance (AMR), epitomized by the proliferation of methicillin-resistant Staphylococcus aureus (MRSA). Marine-derived antimicrobial peptides (AMPs) have emerged as promising alternatives, exhibiting broad therapeutic potential, including antimicrobial and anticancer activities. This review summarizes recent advances in marine AMPs, encompassing resource exploration, preparation methods, and biomedical applications, while addressing challenges such as instability and limited scalability. Future perspectives emphasize rational AMPs design to enhance efficacy and safety, alongside synergistic combination strategies, underscoring the potential of marine AMPs as viable interventions against drug-resistant pathogens.