Coral reefs are among the most ecologically and economically valuable ecosystems on Earth, but they are under threat globally from increasingly frequent and severe marine heatwaves that lead to mass bleaching events. Corals rely on endosymbiotic microalgae (Symbiodiniaceae) for most of their nutrition, yet these critical symbionts are a double-edge sword. When thermally stressed, Symbiodiniaceae are the main producers of excessive reactive oxygen species (ROS), which trigger coral bleaching. The manipulation of coral-associated bacteria to help scavenge ROS and boost coral thermal tolerance has received increasing attention over the past decade. However, the functional role of individual bacterial species in holobiont thermal tolerance is still largely unexplored. This study assesses the ROS-scavenging abilities of bacteria selected as beneficial candidates based on their genomic characteristics. We used a combination of a colorimetric antioxidant assay, bacterial growth measurements under H₂O₂ exposure, and direct H₂O₂ quantification in the growth medium to determine the H₂O₂ scavenging ability of 26 bacterial stains. These experiments provide insights into the antioxidant capabilities of coral-associated bacteria and their potential for enhancing coral resilience under climate change.