The Bons Sinais River defines Quelimane's southern edge and gives the city its coastal character despite lying some distance from the open ocean. The river is part of the Zambezi delta system and connects to the Indian Ocean through a network of mangrove-lined channels. The name, meaning 'Good Signs' in Portuguese, was given by Vasco da Gama who stopped at the estuary in 1498 and noted the hospitable reception from local Swahili traders — one of the earliest recorded European contacts on the Mozambican coast.
The estuary is best seen at dusk when local fishermen return in dugout canoes through the golden light. Basic boat trips can be arranged through guesthouses and small operators in the city — the best give access to the mangrove channels where herons and kingfishers are common. The waterfront area near the Old Cathedral has a promenade of sorts, shaded by mango trees and popular with local residents in the early evening. It is the most pleasant part of the city for a walk and the best place to orient yourself in relation to the river.