Marine dinoflagellates are gaining attention as sustainable bioresource for polyunsaturated fatty acids (PUFAs), particularly omega-3 such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In the present study, we analyzed the FAs and transcriptomic profiles of marine dinoflagellates Amphidinium carterae (D-044) and Prorocentrum minimum (D-127) to evaluate their potential as FAs producers. Gas chromatography-FA methyl ester (GC-FAME) analysis showed that A. carterae is a superior omega-3 producer, yielding a total FA content of 67.6 mg/g DW. DHA accounted for 26.7% of the total FAME profile, which is significantly higher than that of P. minimum (18.1 mg/g DW; DHA 13.1%). Gene Ontology (GO) annotation revealed genes related to FAs and lipid metabolism in A. carterae (1,217 genes) and in P. minimum (2,317 genes), which provide a molecular basis for dinoflagellates with high lipid productivity. Notably, three lipid droplet-associated hydrolase (LDAH) genes with diverse evolutionary origins were identified from A. carterae. These findings suggest a potential expansion of the genetic repertoire related to lipid storage and metabolism, highlighting A. carterae and LDAH as candidates for future biotechnological applications and microalgal metabolic engineering.