Most of Santos that matters to a visitor — the seafront, Gonzaga, the historic centre — is walkable, but distances are deceptive: the beach is 5.3 km from end to end. Local buses run frequently up and down the main avenues. Taxis and rideshares are cheap and easy.
Bicycles are a particularly good way to see the city. The Bike Santos scheme has stations every few hundred metres along the seafront and through the historic centre; a smartphone app handles registration and payments. The bike paths along the seafront and the major canals are well-marked and used by locals as well as tourists.