The natural range of Scylla serrata is in the Indo-Pacific. It is found from South Africa, around the coast of the Indian Ocean where it is especially abundant in Sri Lanka to the Southeast Asian Archipelago, as well as from southern Japan to south-eastern Australia, northern New Zealand, and as far east as Fiji and Samoa. The species has also been introduced to Hawaii and Florida.
In Hawaii, mud crabs are colloquially known as Samoan crabs as they were originally imported from American Samoa. As these crabs are known for their robust size and dense meat content, they have been greatly sought after over the years. As a result of over-crabbing, local government efforts have restricted harvesting of crabs smaller than 6 inches (width across back) and it is illegal to harvest females of any size.