Abstract: Marine fish and shellfish, as a vital source and potential matrix for umami peptides, hold significant promise for replacing traditional flavor enhancers and improving food taste profiles, while also enabling the effective use of low-value fishery byproducts. This review systematically examines the sources, conformational relationships, and flavor characteristics of umami peptides derived from marine products. It further introduces the main umami receptors (the heterodimer T1R1/T1R3 and the metabotropic glutamate receptor mGluR4) involved in umami signal transduction. Emphasis is placed on the preparation of marine umami peptides and the application of artificial intelligence in peptide screening. Additionally, this review explores the impact of thermal processing, microbial fermentation, and enzymatic hydrolysis on the umami characteristics of marine peptides, aiming to provide a scientific reference for advancing research and applications of marine umami peptides in the food seasoning sector.