<p>Diatoms represent the most abundant group of microorganisms carried by ballast water; they present great invasive potential and remain viable after long periods of darkness. This is likely the dispersal route of <i>Coscinodiscus wailesii</i>, a species native to the Indian Ocean or Pacific Ocean, which has become invasive in various global regions. Considering that this species is invasive and potentially harmful, we carried out potential distribution modeling with the aim of assessing the effects of global warming on the geographical distribution of <i>C. wailesii</i>. In this study, we also present the first record of a <i>C. wailesii</i> bloom on the coast of Northeast Brazil, generating low phytoplankton diversity. The distribution models indicated an expansion of the climatic niches for the occurrence of <i>C. wailesii</i> in the SSP2-4.5 scenario (intermediate pathway of greenhouse gas emissions), there was a more marked increase in the climatic niches from the present until 2030, followed by slower growth until 2090. These expansions are more evident in the SSP5-8.5 scenario (greater greenhouse gas emissions) under conditions of more intense global warming. We highlight that these predictions indicate a potential increase in the distribution and frequency of <i>C. wailesii</i> blooms, with important ecological effects. Algal blooms promote greater availability of dissolved oxygen in their initial phase, in addition to representing a temporary carbon sink. However, because <i>C. wailesii</i> is a potentially harmful species, their blooms can cause damage to the ecosystem, such as loss of planktonic diversity and anoxic conditions.</p>