Apple Watch Ultra 3
DROP ITby Apple
Last verified September 13, 2026
💬 — ask a question or share feedback →Apple Watch's blood oxygen feature was legally disabled for US buyers for about 20 months (January 2024-August 2025) after Apple lost a patent case to Masimo, and its restored version now only works by processing data on a paired iPhone rather than the watch itself.
Apple markets blood oxygen (SpO2) monitoring as a core Apple Watch health feature across its lineup, including the Ultra 3, positioning it alongside ECG and heart-rate tracking as part of a comprehensive on-wrist health platform.
The feature has a real, documented history of simply not being available to US buyers. After the US International Trade Commission ruled the blood oxygen sensor infringed two Masimo patents, Apple disabled blood oxygen sensing on US-sold Apple Watches in January 2024 to keep selling the watch at all, and it stayed off for roughly a year and a half. In August 2025 Apple restored a redesigned version -- but the workaround processes the sensor's raw data on a paired iPhone rather than the watch itself, and results can only be viewed on the iPhone, not the watch face. The ITC formally closed the case in April 2026, ending Masimo's ability to revive the ban, but the underlying legal fight ran for over two years.
Blood oxygen monitoring is real Apple Watch functionality today, and the multi-year legal fight is now formally over. But 'core health feature' undersells how fragile it actually was for US buyers: it was legally unavailable for about a year and a half, and even now the redesigned version only works by routing data through a paired iPhone rather than the watch itself -- a real functional downgrade from how it used to work, not a footnote. A feature this central to the health pitch shouldn't have a track record of disappearing over a patent dispute.
- Tom's Guide — As of August 2025, blood oxygen monitoring is available again to US buyers via a redesigned, iPhone-dependent workaround.
- MacRumors — The feature was legally disabled for US-sold Apple Watches from January 2024 to August 2025 -- about 20 months -- due to a lost ITC patent case against Masimo.
Apple Watch Ultra 3 Review – I'm NEVER Going Back! — ZONEofTECH
Why did Apple Watch lose its blood oxygen feature?
The US International Trade Commission ruled that Apple Watch's blood oxygen sensor infringed two Masimo patents, resulting in an import ban. Apple disabled the feature in US-sold watches in January 2024 rather than stop selling the watch entirely.
Does the Apple Watch have blood oxygen monitoring again?
Yes, since August 2025, but through a redesigned workaround: the sensor's raw data is processed on a paired iPhone rather than the watch, and results can only be viewed on the iPhone.