Purpose <p>Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are direct metabolites of ethanol (EtOH) and sensitive biomarkers of alcohol consumption. However, despite extensive studies in Western populations, data on Japanese individuals are limited. This study characterized the pharmacokinetics of EtG and EtS in Japanese adults and evaluated the influence of dose, genetic polymorphisms, and habitual alcohol use.</p> Methods <p>Twenty-eight healthy Japanese adults received either 1.0 or 0.2&#xa0;g/kg of pure EtOH (high or low dose). Whole blood and urine samples were collected for 24&#xa0;h, and EtG and EtS were quantified using validated liquid chromatography–tandem mass spectrometry. Pharmacokinetic parameters were analyzed. The urinary excretion and recovery of EtG and EtS were estimated. Associations between genetic polymorphisms in alcohol-metabolizing and conjugation-related enzymes and Alcohol Use Disorders Identification Test (AUDIT) scores were also evaluated.</p> Results <p>EtG and EtS persisted longer than EtOH in both blood and urine. Both metabolites were excreted in the urine in a dose-dependent manner. Individuals carrying <i>ALDH2*1/*2</i> showed a significantly higher urinary EtG formation rate than those carrying <i>ALDH2*1/*1</i> (wild type). The AUDIT score showed a modest positive association with the urinary formation rate of EtS but not with EtG. The 24&#xa0;h urine from high-dose participants exceeded international cutoffs, whereas that from low-dose participants was below the quantification limits.</p> Conclusions <p>EtG and EtS showed sustained detectability, and their urinary excretion was dose-dependent, indicating their utility as biomarkers of recent alcohol intake. These findings support their potential forensic applications of EtG and EtS in Japan.</p> Clinical trial registration <p>Japan Registry of Clinical Trials (jRCT), jRCT1070240083 (registered 2024-12-10).</p>