<p>Marginal reefs have been identified as potential refugia for coral bleaching amid climate change. However, knowledge on the environmental factors driving coral bleaching in Brazilian reefs, which are among the largest marginal reefs in the world, is still limited. Therefore, we reviewed historical bleaching episodes and investigated the relative influence of environmental conditions for 23 Brazilian reef sites. Specifically, we mean to answer: (1) which regions have historically recorded more marine heatwaves (MHW) and are more susceptible to thermal stress? (2) which regions exhibit consistently high turbidity levels and may therefore represent potential coral climate refugia?, and (3) were there more bleaching episodes in areas with elevated thermal stress and lower turbidity? Satellite data on temperature, thermal anomalies, light incidence, and turbidity of 23 representative reefs along the Brazilian coast, in addition to the bleaching history of the Southwest Atlantic, were collected to answer these questions. Results show that subtropical reefs in Brazil have historically experienced more severe MHW, with intensities ranging from 20 to 100&#xa0;°C&#xa0;d, while also displaying relatively high turbidity levels (&gt; 0.2&#xa0;m⁻¹). Bleaching episodes were mostly concentrated in tropical regions (&gt; 95%), indicating that marine heatwaves are not a primary driver of bleaching susceptibility in Brazil. Although most tropical reefs were historically hit by milder MHW, their low turbidity values (&lt; 0.2&#xa0;m⁻¹) still lead to higher bleaching risk. Our results suggest that Brazilian subtropical reefs, which were previously targeted as potential climate refugia, have suffered from intense marine heatwaves that may overcome the attenuation promoted by water turbidity and surpass the corals’ bleaching threshold.</p>