Itajaí is a municipality located in the state of Santa Catarina, Brazil. Situated on the northern central coast, it sits at the mouth of the Itajaí River at an elevation of approximately 20 feet above sea level. The city is positioned on the right bank of the Itajaí-Açu river mouth and is part of the Vale do Itajaí Mesoregion.
The municipality is a significant economic hub within the state, holding the second-largest gross domestic product in Santa Catarina. Additionally, it is noted for having the highest per capita income in the state.