Apple Watch Enhanced Blood Oxygen Monitoring: What's New in 2025

In early 2024, Apple faced a significant challenge when it had to remove the blood oxygen monitoring feature from the Apple Watch Series 9 and Ultra 2. This decision came after a ruling revealed that Apple's method infringed on existing patents relating to light-based pulse oximetry, held by the California-based company Masimo.

To navigate this issue, Apple removed the feature entirely, allowing it to sidestep an import ban and continue selling these models in the United States. As of today, Apple has triumphantly announced the return of this feature, albeit in a redesigned form, across Series 9, Series 10, and Ultra 2 watches.

According to Apple, this update was made possible by a recent ruling from the U.S. Customs, paving the way for the feature's comeback. The revamped version, designed to avoid Masimo's patent limitations, will transfer sensor data to an iPhone for processing. Users can access the data through the Respiratory section of the Health app on their phones. Previously, this information was directly viewable on the Apple Watch itself.

To access this advanced feature on the Apple Watch Series 9, Series 10, and Ultra 2, users will need to update their device to watchOS 11.6.1, alongside installing iOS 18.6.1 on their iPhones.

It's worth noting that this update will only impact users in the U.S., as international watches were not subject to the import ban. Watches purchased prior to the ban remain unaffected, with the feature still intact on these devices.

The origins of this licensing battle trace back to January 2020, when Masimo initiated a lawsuit against Apple. The claim focused on a breach of trust, as Masimo alleged that after initial talks in 2013 about partnership or possible acquisition, Apple instead hired away Masimo's engineers.