Key Highlights
- Apple is reactivating the Blood Oxygen feature via software updates (iOS 18.6.1 and watchOS 11.6.1) for the U.S.-based Apple Watches Series 9, Series 10, and Ultra 2 that previously had it disabled.
- The redesigned feature now routes data from the watch to the paired iPhone for analysis and display in the Health app’s Respiratory section.
- Apple’s move follows a favorable U.S. Customs ruling, enabling the return of this health function after it was removed due to a patent dispute with Masimo in 2023.
As of August 14, 2025, Apple is rolling out updates, iOS 18.6.1 for iPhones and watchOS 11.6.1 for Apple Watches. These updates re-enable Blood Oxygen monitoring on select models in the U.S. that lost the feature following a patent dispute.
This update applies only to Series 9, 10, and Ultra 2 watches sold without the feature, while other models remain unaffected.
A Two-Device Experience
Instead of processing readings on the watch itself, sensor data will now be calculated by the paired iPhone before being displayed in the Health app. Users must run both watchOS 11.6.1 and iOS 18.6.1 to access the restored function.
Legal Victory Finally Pays Off
The feature’s return follows a U.S. Customs ruling that resolved part of Apple’s legal dispute with Masimo. Apple originally removed Blood Oxygen monitoring from affected models due to an import ban triggered by a 2023 ruling.
This update reinstates a key health feature that was first introduced with Apple Watch Series 6 and became especially relevant during the pandemic.
While the two-device setup may be less convenient, it restores a critical wellness tool for U.S. users. With Apple anticipated to unveil the Series 11 soon, the return of this feature rounds out its broader health-tracking ecosystem.