In 1622, after his father died, he settled around São Paulo; six years later, in 1628, he left the village with the first bandeira composed of 900 settlers and 2000 Tupi warriors.

The bandeirantes first attacked some Guarani villages in the upper Parana valley, which were protected by the Spanish Jesuits and brutally killed many people, capturing 2500 Indians.

[2] This journey allowed the annexation of a portion of the land east of the Uruguay River (current states of Paraná and Santa Catarina) to the Portuguese colony.

Three years later he left again on a new journey, this time to destroy the Spanish Jesuit settlements established southeast of the Uruguay River (current Rio Grande do Sul).

From 1639 to 1642, Tavares fought along with the military which was engaged in war against the Dutch, who had conquered the settlements in the north-eastern coast (Bahia and Pernambuco).