The short answer is a legal one, not a technical one: Apple disabled the Blood Oxygen (pulse oximetry) feature on newer Apple Watch models sold in the United States to comply with a U.S. International Trade Commission (ITC) import ban tied to a patent dispute with medical-device company Masimo. The watch hardware still contained the sensor, but Apple shipped a software change that turned the feature off for U.S. units to keep selling the devices. As of an August 2025 update, Apple has reintroduced the feature in a modified form. This article explains what happened, which watches were affected, and where things stand now.
- The cause was a patent lawsuit and ITC import ban, not a health or safety recall
- Only certain models sold in the US after January 2024 were affected — older watches and units bought abroad kept the feature
- A 2025 software update restored Blood Oxygen in a redesigned form that reads on the paired iPhone
The short version: a patent dispute, not a defect
Blood Oxygen was never disabled because it stopped working or because regulators found it dangerous. It was disabled because of intellectual-property law. Masimo, a company that builds professional pulse oximeters used in hospitals, accused Apple of infringing patents related to measuring blood oxygen saturation (SpO2) with light-based sensors. The ITC — a federal agency that can block imports of products that infringe U.S. patents — agreed in a 2023 ruling and issued an exclusion order.
Because Apple manufactures the Apple Watch overseas and imports it into the U.S., that exclusion order threatened to halt sales entirely. Rather than pull the watches, Apple removed the disputed functionality through a software update so the imported devices no longer performed the patented measurement.
Who is Masimo, and what did the ITC decide?
Masimo is a medical-technology firm specializing in noninvasive monitoring, including the pulse oximetry sensors clipped onto fingers in clinics. The company argued that Apple hired away key personnel and used protected technology to build the Apple Watch’s blood-oxygen sensor. After a multi-year fight, the ITC found in Masimo’s favor and issued a limited exclusion order and cease-and-desist order covering the affected Apple Watch models.
The order took effect in late December 2023. Apple briefly paused sales of the relevant models, then resumed selling them in January 2024 with the Blood Oxygen app disabled on newly sold U.S. units — its chosen path to comply while continuing to sell the hardware.
Which Apple Watches were affected?
The change applied to specific models sold through Apple’s U.S. channels after the ban took effect. Whether your watch has the feature depends on the model, when it was purchased, and where.
| Situation | Blood Oxygen status | Notes |
|---|---|---|
| Series 9 / Ultra 2 bought in US after Jan 2024 | Disabled at launch | Hardware present, feature turned off in software |
| Series 10 (US, 2024) | Disabled at launch | Shipped under the same restriction |
| Series 6, 7, 8 or Ultra (1st gen) | Unaffected | Sold before the order; feature intact |
| Any model bought outside the US | Unaffected | Import ban applies only to US sales |
| US units after Aug 2025 update | Restored (redesigned) | Measurement now displays via the iPhone |
If you already owned an affected watch before the ban and had activated Blood Oxygen, Apple’s disable applied to units sold after the order — it did not retroactively strip the feature from watches that already had it working under earlier software. For a broader look at how these sensors work in the first place, see our explainer on what SpO2 is and how accurate it is.
What “disabled” actually meant
Disabling did not remove the physical sensor. The green-and-red LEDs and photodiodes on the back of the case were still there. What changed was the software layer: on affected U.S. units, tapping the Blood Oxygen app returned a message that the feature was unavailable. Every other health function — heart rate, the ECG feature, high/low heart-rate alerts, and irregular-rhythm notifications — continued to work normally, because those rely on different sensors and patents.
How Apple brought the feature back
In August 2025, Apple released software updates (for the watch and the paired iPhone) that reintroduced Blood Oxygen for affected U.S. models in a redesigned form. Instead of calculating and displaying the reading entirely on the watch, the updated approach has the sensor collect data that is processed and shown in the Health app on the paired iPhone. This design followed a U.S. Customs determination that the reworked implementation fell outside the scope of the import ban.
The practical result for owners: the capability returned, but the experience differs from the original on-watch measurement. If you rely on quick glances at wrist-based metrics, this is a meaningful workflow change worth knowing about.
What this means if you’re buying or using an Apple Watch
- Check the software. Make sure your watch and iPhone are on the latest updates if Blood Oxygen matters to you.
- Know your purchase region. The restriction was specific to U.S.-sold units during the ban window.
- Don’t treat it as a medical device. Wrist SpO2 is a wellness feature, not a clinical oximeter, regardless of the legal status.
- The rest of the health suite is unaffected. If you mainly want ECG, heart-rate, or activity tracking, the dispute never touched those.
Setting up a new watch? Our guide on setting up an Apple Watch for the first time walks through enabling health features during onboarding.
Frequently asked questions
Was the Apple Watch blood oxygen feature disabled because it was inaccurate?
No. The reason was a patent dispute and a resulting U.S. import ban, not a finding about accuracy or safety. Wrist-based SpO2 can vary in accuracy for other reasons, but that was not the cause of the U.S. disable.
Does my older Apple Watch still have Blood Oxygen?
Generally yes. Models sold before the order took effect, and any model purchased outside the United States, were not affected by the import ban.
Can I re-enable Blood Oxygen on an affected watch?
You can’t override it manually, but Apple’s August 2025 software updates restored the feature in a redesigned form for eligible U.S. models. Keep your devices updated to get it.
Did any other Apple Watch health features get turned off?
No. Heart-rate monitoring, ECG, irregular-rhythm notifications, and fitness tracking continued to work. Only the pulse-oximetry (Blood Oxygen) feature was involved.
A note on medical use
This article is general information, not medical advice. Smartwatch blood-oxygen and heart features may flag readings worth discussing, but they cannot diagnose, treat, or rule out any condition. If you have symptoms such as shortness of breath, chest pain, or a health concern about your oxygen levels, talk to a qualified healthcare professional. For related context, see our overview of whether a smartwatch can measure blood pressure accurately.