Guanabara Bay is an oceanic bay located in Southeast Brazil in the state of Rio de Janeiro. On its western shore lies the city of Rio de Janeiro, and on its eastern shore the cities of Niterói and São Gonçalo. Four other municipalities surround the bay's shores. Guanabara Bay is the second largest bay in area in Brazil (after the All Saints' Bay), at 412 square kilometres (159 sq mi), with a perimeter of 143 kilometres (89 mi).
Guanabara Bay is 31 kilometres (19 mi) long and 28 kilometres (17 mi) wide at its maximum. Its 1.5 kilometres (0.93 mi) wide mouth is flanked at the eastern tip by the Pico do Papagaio (Parrot's Peak) and the western tip by Pão de Açúcar (Sugar Loaf).
There are more than 130 islands dotting the bay, including:
Governador – site of Rio de Janeiro's Galeão - Antônio Carlos Jobim International Airport
The bay is crossed by the mighty Rio-Niterói Bridge (13.29 kilometres (8.26 mi) long and with a central span 72 metres (236 ft) high) and there is heavy boat and ship traffic, including regular ferryboat lines. The Port of Rio de Janeiro, as well as the city's two airports, Galeão - Antônio Carlos Jobim International Airport (on Governador Island) and Santos Dumont Airport (on a landfill next to downtown Rio), are located on its shores.