Apple Watch blood oxygen tracking is making a comeback in the United States, ending a legal battle that silenced one of the wearable’s most useful health features for over a year. In August 2025, Apple announced that a US Customs ruling would allow the company to restore the blood oxygen measurement capability to eligible Apple Watch models via software updates iOS 18.6.1 and watchOS 11.6.1. The feature had been disabled since January 18, 2024, following a patent infringement lawsuit from medical technology firm Masimo Corp. and an International Trade Commission injunction.
Key Takeaways
- Apple Watch blood oxygen returns to US Series 9, Series 10, and Ultra 2 via free software update iOS 18.6.1/watchOS 11.6.1.
- Feature was disabled January 2024 due to Masimo patent lawsuit and ITC injunction over pulse oximetry technology.
- Restored blood oxygen data displays in iPhone Health app, not on Watch app, for post-ban purchases.
- Hardware sensors remain in all recent Apple Watch models; only software was disabled in the US.
- Pre-January 2024 purchases and all non-US models retained the feature throughout the dispute.
What Happened to Apple Watch Blood Oxygen
Apple introduced blood oxygen measurement with the Apple Watch Series 6 in 2020, allowing users to track oxygen saturation in their red blood cells with a simple 15-second wrist scan. The feature worked by resting your arm flat on a table or your lap, keeping the Watch display facing up, and holding still while the device measured oxygen levels. For nearly four years, it was a standard health tool alongside heart rate monitoring and ECG capabilities. Then, in late 2023, everything changed. Masimo Corp., a medical technology company, filed a patent infringement lawsuit claiming Apple had stolen its pulse oximetry technology. The US International Trade Commission sided with Masimo, issuing an injunction that forced Apple to disable the feature on new US Apple Watch models effective January 18, 2024. Watches with part numbers ending in LW/A—the US designation—shipped without blood oxygen functionality, while international models and pre-ban purchases remained unaffected.
The removal was controversial. Apple Watch owners who bought Series 9 and Ultra 2 models after the ban discovered they had hardware capable of measuring blood oxygen, but the software was locked out. Pre-January 2024 purchases kept the feature, creating an awkward divide between US customers based on purchase timing. For over 18 months, Apple fought the legal battle while users waited.
How Apple Watch Blood Oxygen Is Returning—and What’s Different
A recent US Customs ruling has given Apple a pathway to restore the feature, though with a redesigned approach. The newly restored blood oxygen measurement will function differently from the original implementation. Instead of displaying results directly on your Apple Watch, the data will now be measured and calculated on your paired iPhone, then viewed in the Health app under Respiratory > Blood Oxygen. This architectural shift may be Apple’s way of satisfying the patent dispute while still delivering the health data users want.
The restoration applies to Apple Watch Series 9, Series 10, and Ultra 2 models purchased in the US after the January 2024 ban. Users with these watches will receive the feature through free software updates coming in late August 2025. The setup process remains straightforward: go to Settings on your Apple Watch, tap Blood Oxygen, and turn on Blood Oxygen Measurements. To measure your oxygen levels, you’ll rest your arm on a table with your wrist flat, ensure the Watch display faces up, and hold still for 15 seconds while the sensor captures the reading.
The Masimo Patent War Continues Despite Resolution
While the US Customs ruling allows blood oxygen to return, the underlying dispute with Masimo remains unresolved. Masimo has alleged that Apple stole its pulse oximetry technology and even recruited insiders from the medical company. Apple counters that Masimo copied the Apple Watch design with its own W1 smartwatch, launched in 2022. Despite a CEO change at Masimo in February 2025 and Apple’s appeal of the original ITC ruling, no settlement has been reached as of mid-2025. The restoration of blood oxygen via US Customs ruling represents a workaround rather than a true legal victory, allowing both companies to claim some vindication while the patent dispute simmers in the background.
Should You Enable Apple Watch Blood Oxygen
Apple emphasizes that the blood oxygen feature is not intended for medical diagnosis or treatment. Instead, it’s designed to help you track overall wellness and identify trends in your oxygen saturation over time. If you have an eligible US Apple Watch and receive the software update, enabling the feature is straightforward and costs nothing. Simply go to your Watch settings and toggle on Blood Oxygen Measurements. You can then view historical data in your iPhone Health app under Respiratory > Blood Oxygen, building a personal baseline of your typical oxygen levels.
How do I measure blood oxygen on Apple Watch
To measure your blood oxygen, open the Blood Oxygen app on your Apple Watch, rest your arm flat on a table or your lap with the Watch display facing up, and tap Start. Hold your arm still for the 15-second countdown while the sensor reads your oxygen saturation. For best results, wear your Watch snugly but not too tight, and ensure the sensor on the back of the Watch makes full contact with your wrist.
Will blood oxygen work on older Apple Watch models
The restored blood oxygen feature applies only to Apple Watch Series 9, Series 10, and Ultra 2 models purchased in the US after January 18, 2024. Earlier models like Series 8 and earlier, as well as all non-US models, are not part of this rollout. If you purchased a Series 9 or Ultra 2 before the January 2024 ban, your watch never lost the feature.
Apple’s restoration of blood oxygen marks the end of a frustrating chapter for US Apple Watch owners, though the legal dispute with Masimo shows no signs of ending. For those with eligible watches, the return of this health feature—even in redesigned form—restores one of the Apple Watch’s most compelling reasons to upgrade. The fact that it took a patent war, an ITC injunction, and a US Customs ruling to bring back a feature users already owned speaks to the complexity of health technology patents and the collateral damage that legal disputes inflict on consumers.
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This article was written with AI assistance and editorially reviewed.
Source: TechRadar
