On 28 January 1808, by Royal Charter, the Prince Regent D. João authorised the opening of the ports to friendly nations. The decision was seen as an important step toward Brazil's independence, because while other colonies could only trade with colonising countries or with the metropole, Brazil could now act as a free nation, with the right to export "all types of goods and colonial products".

On 12 July 1808, by decree of the Prince Regent, the first pilotage services were organised in Brazil, primarily in the ports of Salvador, Santos, Rio de Janeiro and Recife. Through this decree, the entry and exit of vessels was conducted in safety.

With the creation of the State of Maranhão Harbourmaster on 28 July 1846, emerged on 22 September 1856, the Pilots\' Association of the Bar and Bay of São Marcos, with Head Office at Parque 15 de Novembro, 232, São Luís Downtown, a townhouse that to this day shows a helm in high relief. Its personnel comprised three pilots, a trainee pilot, a clerk and three rowers. The methods used to transport the pilots to the vessels that were docked in the Bay of São Marcos were restricted to an iron whaling boat and a wooden canoe.

The mooring bay of the Port of São Luís was located at the palace bulwark in front of the Sagração Quay, Campos Melo ramp, completed in 1844.

In 1850, the silting effects at the Port of São Luís were already been felt: it was hard to find a good mooring zone and places for unloading of ships, which was done by lighter boats.

Many were the reasons behind the attempts to move the Port's location, and thus, from 1890 discussion on the Port of Itaqui began. In 1893, references to Itaqui began appearing in the press, with emphasis on the location, accessibility at all times, better draught, and being in the vicinity of Ilha do Medo [Medo Island] in order to serve as a lookout point.

In 1956, building of the Port of Itaqui began, and it was opened in 1970 along with the Bacanga Dam, which would provide access to the Port. The following year, the old Port of São Luís was decommissioned, with Itaqui having assumed all of the maritime activities.

In 1983, the ALUMAR Port Terminal was inaugurated, when the vessel "Alamoa" unload the first cargo of bauxite, and in 1986, the Maritime Terminal of Ponta da Madeira (VALE) became operational.

The challenges of the venture gave way to the tranquillity of being able to rely on modern and fully-equipped ports with functional vessels that ensured comfort and security to its users. Pilotage has changed and is nowadays one of the best and most reliable in the country.