Some good places to purchase seaweed include OHSV.net and AsianFoodGrocer.com. Seaweed is also called nori in Japanese cuisine, and it is an essential part of sushi, onigiri, miso soup. It is also often enjoyed by itself.
Ocean Harvest Sea Vegetable Company offers seaweed that is tested for radioactive isotopes caused by the Fukushima nuclear power plant accident. It is located in Northern California and harvests all of its products by hand in a sustainable fashion. AsianFoodGrocer.com sells a wide variety of sushi imported from Japan. Some of its products include Shisho Kombu Perilla Flavored Seaweed, Noriichi Roasted Sushi Nori and Orchids Roasted Sushi Nori.