In the U.S., affected Apple Watch Series 9, Series 10, and Ultra 2 models can use Apple’s redesigned Blood Oxygen feature after the paired iPhone is updated to iOS 18.6.1 and the watch to watchOS 11.6.1. The watch collects the sensor data, but the paired iPhone analyzes it; find results in Health > Search > Respiratory > Blood Oxygen.
Apple’s current instructions say to use the latest compatible iOS and watchOS. Check the watch model, purchase details, and regional availability before troubleshooting: the redesigned workflow applies to some affected U.S. watches, not every Apple Watch.
Which Apple Watches support Blood Oxygen?
Apple says Blood Oxygen is available on Apple Watch Series 6 or later and all Apple Watch Ultra models, subject to country or region availability. Apple Watch SE models do not support the feature.
For the U.S. redesign, Apple announced availability for some Series 9, Series 10, and Ultra 2 users whose watches did not have the original feature. Apple’s current support guidance identifies U.S.-purchased watches bought on or after January 18, 2024 with part numbers ending in LW/A or LS/A as using iPhone-side analysis.
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Apple says U.S. units previously purchased with the original feature and units purchased outside the U.S. were not affected by the redesign. Regional availability still varies; check Apple’s watchOS feature availability reference for your region.
How to get Blood Oxygen working again
1. Confirm that the watch is eligible
Check that the watch is a supported Series 6 or later or an Ultra model, and that Blood Oxygen is available in your region. If you have an affected U.S. unit, check its purchase date, model, and part-number suffix. Apple Watch SE models do not support Blood Oxygen.
2. Update the paired iPhone
On the iPhone paired with the watch, open Settings > General > Software Update and install the latest iOS version available for that iPhone. Apple specified iOS 18.6.1 for the redesigned U.S. feature; its current support instructions say to use the latest available iOS.
3. Update the Apple Watch
On the paired iPhone, open the Watch app and go to My Watch > General > Software Update. Install the latest watchOS available for your watch. Apple specified watchOS 11.6.1 for the redesigned U.S. feature and currently advises using the latest available watchOS.
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4. Check that the Blood Oxygen app is installed
Search the apps on the watch for Blood Oxygen. If it is missing, check regional availability and search for it in the App Store on the watch; reinstall it there if it was deleted.
5. Take a Blood Oxygen measurement
- Wear the watch snugly but comfortably, with its back touching your skin.
- Open the Blood Oxygen app on the watch.
- Rest your arm on a stable surface with your wrist flat and the watch facing up.
- Tap Start and remain still for 15 seconds while the measurement completes.
If your wrist bone interferes with the watch, Apple suggests moving the watch 2.5 to 5 cm above it. Movement, cold-related low skin perfusion, tattoos under the sensor, some arm or hand positions, and a resting heart rate above 150 bpm can interfere with a reading, according to Apple Support.
6. Find the saved result on the iPhone
On the iPhone paired with the watch, open Health > Search > Respiratory > Blood Oxygen. Apple says readings can be viewed by day, week, month, or six months, and filtered for sleep or high-elevation readings.
What changed for affected U.S. Apple Watch owners?
Apple announced the redesigned U.S. workflow on August 14, 2025 for some Series 9, Series 10, and Ultra 2 owners whose watches lacked the original feature. With the required updates, the watch sensor collects the data and the paired iPhone calculates the result, which appears in the Health app’s Respiratory section.
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| Watch situation | What to expect |
|---|---|
| Affected U.S. Series 9, Series 10, or Ultra 2 without the original feature | After the required updates, the paired iPhone analyzes the sensor data and displays results in Health. |
| U.S. unit previously purchased with the original feature | Apple says it was not affected by the redesign in the same way. |
| Unit purchased outside the U.S. | Apple says it was not affected by this U.S. update; local availability may vary. |
| Apple Watch SE | Blood Oxygen is not supported. |
For the specified U.S. models, a secondary iPhone that is not paired with the watch cannot perform the analysis. Use the paired iPhone to check results.
Troubleshooting: Blood Oxygen still does not appear
The watch is compatible, but the app is missing
Check regional availability, then search for Blood Oxygen in the App Store on the watch and reinstall it if it was deleted. Confirm that you updated the iPhone paired with the watch and the watch itself.
The app opens but will not complete a measurement
- Wear the watch snugly but comfortably, with its back against your skin.
- Keep your wrist flat, facing up, and supported on a stable surface.
- Remain still for the full 15 seconds.
- If your wrist bone interferes, move the watch 2.5 to 5 cm above it.
- Consider whether cold, a tattoo under the sensor, arm or hand position, or a resting heart rate above 150 bpm is affecting the measurement.
Apple cautions that a reliable reading may not be possible every time, even in ideal conditions.
The result is not in the Health app
On the paired iPhone, open Health > Search > Respiratory > Blood Oxygen. For the redesigned U.S. workflow, do not rely on a secondary iPhone that is not paired with the watch to analyze the data.
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The feature is unavailable in the user’s region
Availability varies by country or region. Check Apple’s feature availability reference. Updating software does not override every regional restriction.
The watch is an SE
Apple Watch SE models do not support Blood Oxygen, so a software update cannot add the feature.
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Apple says measurements from the Blood Oxygen app are intended for general fitness and wellness, not medical use or self-diagnosis. The app is designed for people aged 18 and older.
Apple says many people measure between 95% and 100%, while some healthy people normally measure below 95% and readings during sleep may be lower. These figures are context, not a diagnosis or a universal pass/fail threshold.
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If you feel unwell or are concerned about a reading or trend, contact a qualified healthcare professional rather than relying on a watch measurement to interpret it.
FAQ
Which U.S. Apple Watches can use the redesigned Blood Oxygen feature?
Apple announced the redesign for some U.S. Series 9, Series 10, and Ultra 2 watches that lacked the original feature. Apple’s support guidance also identifies qualifying U.S.-purchased models bought on or after January 18, 2024 with part numbers ending in LW/A or LS/A as using iPhone-side analysis.
Which updates are required for the redesigned U.S. feature?
Apple specified iOS 18.6.1 on the paired iPhone and watchOS 11.6.1 on the watch. Apple’s current instructions say to use the latest available compatible versions.
Where do I find Apple Watch Blood Oxygen results?
On the iPhone paired with the watch, open Health, tap Search, choose Respiratory, and then choose Blood Oxygen.
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Apple says a secondary iPhone that is not paired with the watch cannot perform the analysis for the specified U.S. models. Check results on the paired iPhone.
Does Apple Watch SE have Blood Oxygen?
No. Apple Watch SE models do not support the Blood Oxygen app.
Why might a measurement fail?
Movement, cold-related low skin perfusion, tattoos under the sensor, certain arm or hand positions, and a resting heart rate above 150 bpm can interfere. Keep the watch snug, support the arm, hold the wrist flat, and remain still for 15 seconds.
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Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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