Apple Watch blood oxygen feature returns to the U.S. in Series 9, 10 & Ultra 2. Learn how the updated watchOS redesign works and how to use it.
Apple Watch Blood Oxygen Feature Returns in the U.S. — Here’s Everything You Need to Know
After 18 months of absence, Apple Watch blood oxygen monitoring is officially back in the United States. Following a patent dispute with medical technology company Masimo, Apple has devised a redesigned solution that restores the feature for newer Apple Watch Series 9, Series 10, and Apple Watch Ultra 2 users.
This comprehensive guide explains the update, technology, compatibility details, and the legal battle that led to this change — plus how you can start using it again.
Why the Blood Oxygen Feature Matters
The Apple Watch blood oxygen sensor uses a series of red, green, and infrared LEDs, along with photodiodes, to measure the amount of oxygen in your blood (SpO₂). This metric — expressed as a percentage — helps you understand your respiratory health, fitness performance, and sleep quality.
During the height of the COVID-19 pandemic, blood oxygen monitoring became one of the smartwatch’s most valued health features, especially for identifying potential issues before symptoms intensified.
The Patent Dispute Explained
The feature’s removal in early 2024 was not due to technical failure — it was because of a patent infringement ruling.
- Masimo, a leader in hospital-grade pulse oximetry, claimed Apple used its patented technology without permission.
- In January 2023, the U.S. International Trade Commission (ITC) sided with Masimo, issuing an import ban on Apple Watches with the blood oxygen feature.
- The ban took full effect on January 17, 2024, forcing Apple to sell modified U.S. models without blood oxygen monitoring.
The Redesigned Blood Oxygen Feature
On August 14, 2025, Apple released iOS 18.6.1 and watchOS 11.6.1, restoring the feature in the U.S. — but with a twist.
- How it works now: The Apple Watch still collects raw sensor data, but it sends it to the paired iPhone for processing, avoiding Masimo’s patent claims.
- Results appear in the Health app → Respiratory section on the iPhone, not directly on the watch face.
- Core accuracy remains the same, Apple claims — only the computation location has changed.
Compatible Devices
The restored feature applies to:
- Apple Watch Series 9 (U.S. models sold after Jan 17, 2024)
- Apple Watch Series 10
- Apple Watch Ultra 2
Note:
- Apple Watches sold before the ban or outside the U.S. still have the original on-watch processing.
- Users must update to iOS 18.6.1 (iPhone) and watchOS 11.6.1 (Apple Watch).
How to Use the New Blood Oxygen App
Follow these steps to take a measurement:
- Update your devices to iOS 18.6.1 and watchOS 11.6.1.
- Open the Blood Oxygen app on the Apple Watch.
- Sit still, rest your wrist on a flat surface, and start the reading.
- Wait for 15 seconds while the watch collects the data.
- Open the Health app on your iPhone to view results and historical trends.
Benefits & Limitations
Benefits
- Restored access to SpO₂ data in the U.S.
- Continuous background monitoring during day and night.
- Identical measurement process and accuracy compared to original design.
Limitations
- Results no longer appear instantly on the watch.
- Requires access to your paired iPhone to check measurements.
- Still not a replacement for medical-grade devices.
Impact on Apple and the Industry
- Apple’s workaround avoids further customs bans while keeping one of its most marketable health features.
- This move strengthens the Apple Watch’s position against rivals like Samsung and Google.
- For the tech industry, it’s a case study in using software innovation to navigate patent restrictions.
Future Outlook
- Apple continues appealing the ITC’s decision — if successful, the on-watch processing version could return before Masimo’s patents expire in 2028.
- The redesign might influence how other wearable makers handle similar legal issues in the health-tech space.
- Official Apple Support: How to use the Blood Oxygen app on Apple Watch
https://apple.co/4Gb2T1D - Apple Support: Measure blood oxygen levels on Apple Watch (includes update info for US models post-Jan 2024)
https://apple.co/3CN9b9R - TechCrunch article on the redesigned Apple Watch Blood Oxygen feature return (Aug 2025)
https://tcrn.ch/4DTMfZj - The New York Times report on Apple restoring Blood Oxygen feature after patent dispute
https://nyti.ms/4DPOU4W - Apple official PDF white paper: Blood Oxygen app on Apple Watch (technical details & accuracy)
https://apple.co/3NCJlmY
