Background: Information on the contents of both vitamin B{}_{12} and folate in edible seaweeds is limited, of which deficiencies disrupt methionine biosynthesis to accumulate homocysteine as a risk factor of cardiovascular diseases. Methods: Both vitamins were determined in commercially available edible seaweed products using high-performance liquid chromatography. Results: Dried purple laver (Neopyropia yezoensis) products contain higher levels of vitamin B{}_{12} (approximately 30–60 \mug/100 g dry weight) and folate compounds (approximately 880–1300 \mug/100 g dry weight) than other seaweed products, such as kombu (Saccharina japonica), hijiki (Sargassum fusiformis), and wakame (Undaria pinnatifida). 5-methyltetrahydrofolate was the major folate compound in purple laver products. 5-formyltetrahydrofolate was found at a moderate level, whereas tetrahydrofolate, 5,10-metenyltetrahydrofolate, 10-formyltetrahydrofolate, and folic acid were found to be minor folate compounds. Conclusions: These findings suggest that dried purple laver (nori) products are suitable sources of vitamin B{}_{12} and folate compounds for humans, especially vegetarians.