Thanh Quốc is a family-owned Vietnamese producer of traditional fish sauce from Phú Quốc Island. The family’s experience in the craft has been passed down through at least three generations, while the Thanh Quốc production facility was officially established in 1993. The business is currently operated by Thanh Quốc Fish Sauce Production and Trading Company Limited. Its owner, Nguyễn Thị Tịnh, has played an important role in preserving and promoting the island’s traditional fish sauce. From 2000 to 2015, she served three terms as president of the Phú Quốc Fish Sauce Association. She also participated in the international protection of the Phú Quốc name, which is registered as a protected designation of origin in the European Union. The principal ingredients are anchovies caught in the waters surrounding Phú Quốc and sea salt from the Bà Rịa–Vũng Tàu region. The fish is combined with salt and naturally fermented in large traditional wooden barrels. Production, extraction of the matured sauce and bottling are all carried out on the island to meet the requirements of the Phú Quốc geographical indication. The range includes several fish sauces distinguished by their natural nitrogen content and the concentration of compounds produced through the breakdown of fish proteins. The finished sauce has a clear amber to reddish-brown colour, a pronounced umami character and the savoury-sweet finish typical of traditional Phú Quốc fish sauce.