Objective. Accurate arterial occlusion pressure (AOP) measurement is essential for individualized blood flow restriction (BFR) prescription, but no automated BFR device has been validated across the range of body positions commonly used in practice. This study evaluated the validity, tolerability, and feasibility of automated algorithm-based AOP measurement compared to pulsed-wave Doppler ultrasound across supine, seated, and standing positions. Approach. Forty-six healthy adults completed AOP measurements on the dominant lower limb using both automated and Doppler ultrasound methods at three body positions in randomized order. Validity was assessed using intraclass correlation coefficients (ICC), Bland–Altman analysis, and proportional bias testing. Tolerability was evaluated through measurement duration, pain perception (0–10), and adverse event surveillance. Feasibility was assessed by the first-attempt success rate. Main results. The automated method demonstrated good agreement with Doppler ultrasound in supine (ICC = 0.76), seated (ICC = 0.87), and standing (ICC = 0.83) positions. However, 95% limits of agreement ranged from −38 to +48 mmHg across positions, and a significant negative proportional bias was observed in supine (p = 0.031). Automated measurements required significantly longer duration than Doppler across all positions (p < 0.001), while pain perception was comparable between methods. A single participant withdrew during standing automated measurement due to intolerable pain. The first-attempt success rate was significantly lower for automated measurement in standing compared to Doppler (87% vs 100%, p = 0.041) but comparable in supine and seated. Significance. The automated device demonstrates good validity and acceptable tolerability for AOP assessment in healthy young adults during seated and standing positions. Clinicians should consider manual ultrasound verification for supine measurements or when prescribing high-percentage AOP protocols, and provide postural support during standing measurements to improve first-attempt success.