Calcareous benthic foraminifera can develop pores in their test wall to facilitate gas exchanges (e.g., O2, CO2) with the surrounding seawater. The patterns of these pores, i.e., porosity, pore density, and pore size, can vary based on environmental factors, including bottom water dissolved oxygen concentration (BWDO). Specifically, some species react with increased test porosity to lower BWDO levels, highlighting their proxy potential for reconstructing past BWDO concentrations. To validate this proxy in the Southeast Pacific (SEP), the pore patterns of six benthic foraminifera species were compared with BWDO. The specimens, dated Holocene to modern, were collected from surface sediment samples along the SEP (12°–44°S) from 24 to 3,252 m water depth. Porosity, pore density, and pore size were measured on the umbilical and spiral sides, including all visible chambers, and the penultimate and antepenultimate chambers (PAC) on both sides. Our study reveals species-specific pore pattern responses to BWDO, with most species increasing their test porosity to adapt to lower BWDO. Notably, Cibicidoides species show increased porosity on the umbilical side, whereas Planulina species do so primarily on the spiral side. This indicates that using the pore patterns of several species together is not recommended in the SEP. Instead, focusing on individual species provides stronger inverse correlations between BWDO, porosity, and pore density, especially for C. wuellerstorfi. These findings support the use of benthic foraminifera pore patterns as reliable indicators for reconstructing quantitively past BWDO, with an error range down to ±5–20 µmol/kg.