1. Supermarket: Natto can be found in some large supermarkets, such as Yuhua Domestic Products, Jurong West Fresh Food Market and Japan Food Center.
2. Japanese food store: If you find a Japanese food store in Singapore, you can definitely buy natto there. Some common Japanese restaurants are: Manchu Japanese Fresh Food, Avalon Hokkaido Japanese Food, Yamachan and so on.
3. Online shop: If you can't find a physical store of natto in Singapore, you can buy it in an online shop. Some common online stores include: RedMart, Chinatown Point, etc.
When buying natto, please pay attention to the shelf life and production date to ensure that you buy fresh natto. In addition, if you have special requirements for the taste and flavor of natto, you can consult the clerk or check the product description when purchasing.