The dengue virus (DENV), of genus Flavivirus (Flaviviridae), has four antigenically distinct serotypes, of which DENV-3 is classified into five genotypes. Here, we describe the detection of DENV-3 genotype I in sera of a Brazilian patient returning from Singapore to Rio de Janeiro, Brazil by using multiplex real-time RT-PCR, Sanger sequencing of the whole envelope protein, and phylogenetic analysis. The virus shares ancestry with those identified in Bali, Indonesia in 2015. Because of tourism and mass events occurring in the last four years (World Youth Day, World Cup, Olympics), arboviruses, such as Chikungunya genotype ECSA, DENV-4 Genotype I, and Zika, from other continents have been introduced in Brazil