Background: Hot spring bathing is practiced to manage various diseases, including hypertension. We investigated the preventive effects on hypertension of hot spring bathing for older adults in a data analysis using responses to a previous questionnaire with the aim to identify a novel approach in the prevention and management of hypertension.Methods: Among 10428 adults aged ≥65 years, we assessed the hot spring bathing habits in the 4001 subjects with a history of hypertension. Odds ratios (OR) with 95% confidence intervals (CIs) were calculated using a multivariable logistic regression model for the history of hypertension.Results: In a multivariable logistic regression model, age (≥85 years; OR, 1.410; 95% CI, 1.180–1.690), history of arrythmia (OR, 1.580; 95% CI, 1.380–1.820), stroke (OR, 1.590; 95% CI, 1.280–1.980), gout (OR, 1.900; 95% CI, 1.540–2.330), diabetes mellitus (OR, 1.470; 95% CI, 1.310–1.650), hyperlipidemia (OR, 1.680; 95% CI, 1.490–1.910), renal disease (OR, 1.500; 95% CI, 1.220–1.860) chronic hepatitis (OR, 0.648; 95% CI, 0.494–0.849), and hot spring bathing for 20–29 min (OR, 0.817; 95% CI, 0.715–0.934) and at 19:00 or later (OR, 0.884; 95% CI, 0.715–0.934) were independently and significantly associated with hypertension during the lifetime. Conclusions: These results support our hypothesis that habitual nighttime hot spring bathing is associated with improved hypertension control. The findings suggest that nighttime hot spring bathing might help in preventing hypertension owing to chronic stress-induced sleep disturbance in adults aged >65 years.