Shimanto is a city in southwestern Kōchi Prefecture, Japan. It is located in the southwestern part of the prefecture, on the island of Shikoku. The city covers a total area of 632.29 square kilometres (244.13 square miles).
As of 31 July 2022, Shimanto had an estimated population of 32,593 living in 16,635 households, giving it a population density of 52 persons per square kilometre.