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Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Blood Oxygen monitoring returned to certain U.S.-sold Apple Watch units on August 14, 2025, after Apple released iOS 18.6.1 and watchOS 11.6.1. The restoration covers some Series 9, Series 10, and Apple Watch Ultra 2 watches that originally shipped without the feature because of the Masimo patent dispute.
It is not a universal switch-on, and it is not exactly the old experience: the watch gathers the sensor data, but the paired iPhone performs the calculation and stores the result in the iPhone Health app under Browse → Respiratory → Blood Oxygen.
Which Apple Watches qualify?
| Model or situation | What to expect |
|---|---|
| U.S. Apple Watch Series 9 | Eligible if the particular unit previously lacked Blood Oxygen; Apple says the redesigned feature is added after the required updates. |
| U.S. Apple Watch Series 10 | Eligible if it was sold without Blood Oxygen; results use the paired iPhone. |
| U.S. Apple Watch Ultra 2 | Eligible if the unit previously lacked the feature and receives the required updates. |
| Series 6, 7, 8, or original Ultra that already had Blood Oxygen | These watches are not “getting it back”; Apple says units purchased with the original feature are unaffected. |
| Apple Watch SE | Do not assume eligibility. Apple’s Blood Oxygen documentation describes support from Series 6 onward and excludes the first-generation SE; the 2025 restoration announcement names only Series 9, Series 10, and Ultra 2. |
| Series 11 and Ultra 3 | These later-generation watches are separate from the restoration of older affected models. Apple’s launch material lists Blood Oxygen among their health features. |
| Watch purchased outside the United States | Apple says international units were unaffected by this U.S. change and retain their applicable regional behavior. |
Model name alone is not enough. Sales region, original hardware configuration, and possible service-replacement history can change the result. Apple’s wording is “some” users, not every Series 9, Series 10, or Ultra 2.
Apple’s August 2025 announcement identifies the affected models and regional limits.
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![Apple Watch SE 3 [GPS 40mm] Smartwatch with Starlight Aluminum Case with Starlight Sport Band - S/M. Fitness and Sleep Trackers, Heart Rate Monitor, Always-On Display, Water Resistant](https://m.media-amazon.com/images/I/31YiTby0pOL._SL160_.jpg)
- GET SMARTER HEALTH INSIGHTS—Apple Watch SE 3 is an advanced health tracker that helps you better understand your body. The smartwatch sends alerts for an irregular heart rhythm, or an unusually high or low heart rate.* You can view your overnight health tracking metrics with the Vitals app,* track your sleep score, and get sleep apnea notifications.*
- A GREAT FITNESS TRACKER—SE 3 can track your workouts in a healthy number of ways—from running and strength training to simply achieving your 10K steps a day. With real-time metrics and Workout Buddy powered by Apple Intelligence from your nearby iPhone,* you’ll hit your goals like never before.
- KEEP HELP CLOSE AT HAND—SE 3 is a smartwatch that can detect a hard fall or severe car crash and automatically help connect you to emergency services and notify your emergency contacts.* Check In can automatically notify a loved one when you’ve arrived at your destination.
- WOMEN’S HEALTH INSIGHTS—SE 3 has advanced sensors that track your wrist temperature while you sleep. With this smartwatch, you can log your periods and symptoms, get period predictions, and get notified of cycle deviations.*
- GREAT BATTERY LIFE AND FASTER CHARGING—Enjoy a smartwatch with all-day, 18-hour battery life* from sunup to sundown. Then charge up to twice as fast as SE 2* and get up to 8 hours of battery in just 15 minutes.*
What actually returned?
Apple restored a redesigned Blood Oxygen experience rather than simply re-enabling the original on-watch workflow.
- The watch’s optical sensor collects the data.
- The paired iPhone performs the measurement calculation.
- The result is saved and viewed in the iPhone Health app’s Respiratory section.
That means affected U.S. owners should not expect the same immediate results screen on the watch that earlier supported models used. The iPhone is an essential part of the new process.
Rank #2
![Apple Watch Series 11 [GPS 42mm] Smartwatch with Rose Gold Aluminum Case with Light Blush Sport Band - S/M. Sleep Score, Fitness Tracker, Health Monitoring, Always-On Display, Water Resistant](https://m.media-amazon.com/images/I/31caPPnRysL._SL160_.jpg)
- A FULL-FEATURED HEALTH TRACKER—Apple Watch Series 11 gives you invaluable insights about your body, right from your wrist. Take an ECG anytime* and get alerts for a high and low heart rate or an irregular rhythm*—so you can stay closer to your heart. You can also view your overnight health tracking metrics with the Vitals app* and be notified of possible sleep apnea.*
- KNOW YOUR SLEEP SCORE—With advanced sleep tracking, Series 11 gives you a daily sleep score. It’s an easy way to help measure and understand the quality of your sleep, so you can make it more restorative.
- GET HYPERTENSION NOTIFICATIONS—Did you know that Series 11 can spot signs of chronic high blood pressure? By analyzing how your blood vessels respond to beats of the heart, it can notify you of possible hypertension.*
- SAFETY FEATURES—A smartwatch that puts your safety first. Series 11 can detect a hard fall or severe car crash, automatically help connect you with emergency services, and notify your emergency contacts.* Check In can automatically notify a loved one when you’ve arrived at your destination.
- A POWERFUL FITNESS TRACKER—With advanced metrics and motivating features like Pacer, Heart Rate Zones, training load, and Workout Buddy powered by Apple Intelligence from your nearby iPhone*—Series 11 is made to help everyone stay active, from runners and hikers to strength-training enthusiasts.
| Original supported experience | Redesigned U.S. experience |
|---|---|
| Blood Oxygen was enabled in the watch’s supported regional configuration. | Software restores the feature on qualifying U.S. units that shipped without it. |
| The watch-centered workflow provided the result. | The watch collects data while the paired iPhone calculates it. |
| Results followed the original watch app experience. | Results appear in iPhone Health → Respiratory → Blood Oxygen. |
Why was Blood Oxygen removed from U.S. models?
Masimo, a medical-technology company, accused Apple of infringing pulse-oximetry patents. The U.S. International Trade Commission found infringement, contributing to an import restriction. Apple consequently sold modified U.S. watches without usable Blood Oxygen.
- 2020: Apple introduced Blood Oxygen with Apple Watch Series 6.
- December 2023: The import dispute disrupted U.S. sales of affected watches.
- January 2024: replacement U.S. versions shipped without usable Blood Oxygen.
- August 14, 2025: Apple introduced the iPhone-dependent redesign through iOS 18.6.1 and watchOS 11.6.1.
- March–April 2026: an ITC judge found the redesigned watches did not infringe Masimo’s patents, and the ITC declined review, removing the immediate threat of a renewed import ban.
Background reporting on the original restriction is available from MacRumors and The Associated Press. The later legal development was reported by Reuters via Investing.com. This does not mean every Masimo-related lawsuit or appeal has permanently ended.
Rank #3
![Apple Watch Series 11 [GPS 46mm] Smartwatch with Jet Black Aluminum Case with Black Sport Band - M/L. Sleep Score, Fitness Tracker, Health Monitoring, Always-On Display, Water Resistant](https://m.media-amazon.com/images/I/416RQ0rtsUL._SL160_.jpg)
- A FULL-FEATURED HEALTH TRACKER—Apple Watch Series 11 gives you invaluable insights about your body, right from your wrist. Take an ECG anytime* and get alerts for a high and low heart rate or an irregular rhythm*—so you can stay closer to your heart. You can also view your overnight health tracking metrics with the Vitals app* and be notified of possible sleep apnea.*
- KNOW YOUR SLEEP SCORE—With advanced sleep tracking, Series 11 gives you a daily sleep score. It’s an easy way to help measure and understand the quality of your sleep, so you can make it more restorative.
- GET HYPERTENSION NOTIFICATIONS—Did you know that Series 11 can spot signs of chronic high blood pressure? By analyzing how your blood vessels respond to beats of the heart, it can notify you of possible hypertension.*
- SAFETY FEATURES—A smartwatch that puts your safety first. Series 11 can detect a hard fall or severe car crash, automatically help connect you with emergency services, and notify your emergency contacts.* Check In can automatically notify a loved one when you’ve arrived at your destination.
- A POWERFUL FITNESS TRACKER—With advanced metrics and motivating features like Pacer, Heart Rate Zones, training load, and Workout Buddy powered by Apple Intelligence from your nearby iPhone*—Series 11 is made to help everyone stay active, from runners and hikers to strength-training enthusiasts.
Updates required to restore it
Apple introduced the restoration with:
- iOS 18.6.1 on the paired iPhone
- watchOS 11.6.1 on the Apple Watch
Readers in 2026 may be running later releases. Install the current supported versions for both devices; Apple’s watchOS 11.6.1 notes describe the new U.S. Blood Oxygen experience. Do not update only one device.
How to set it up and take a reading
- Back up the iPhone and Apple Watch if appropriate.
- Update the paired iPhone and watch to the required release or a later supported release.
- Keep the watch paired with that iPhone.
- Open the Health app on the iPhone.
- Choose Browse → Respiratory → Blood Oxygen.
- Complete any setup or permissions prompts.
- Wear the watch snugly with good skin contact and keep your wrist still during a reading.
Fit, movement, temperature, circulation, and skin contact can affect readings. Apple’s technical documentation is available in its Blood Oxygen support document.
Rank #4
![Apple Watch SE 3 [GPS 40mm] Smartwatch with Midnight Aluminum Case with Midnight Sport Band - S/M. Fitness and Sleep Trackers, Heart Rate Monitor, Always-On Display, Water Resistant](https://m.media-amazon.com/images/I/31Gq8SToFJL._SL160_.jpg)
- GET SMARTER HEALTH INSIGHTS—Apple Watch SE 3 is an advanced health tracker that helps you better understand your body. The smartwatch sends alerts for an irregular heart rhythm, or an unusually high or low heart rate.* You can view your overnight health tracking metrics with the Vitals app,* track your sleep score, and get sleep apnea notifications.*
- A GREAT FITNESS TRACKER—SE 3 can track your workouts in a healthy number of ways—from running and strength training to simply achieving your 10K steps a day. With real-time metrics and Workout Buddy powered by Apple Intelligence from your nearby iPhone,* you’ll hit your goals like never before.
- KEEP HELP CLOSE AT HAND—SE 3 is a smartwatch that can detect a hard fall or severe car crash and automatically help connect you to emergency services and notify your emergency contacts.* Check In can automatically notify a loved one when you’ve arrived at your destination.
- WOMEN’S HEALTH INSIGHTS—SE 3 has advanced sensors that track your wrist temperature while you sleep. With this smartwatch, you can log your periods and symptoms, get period predictions, and get notified of cycle deviations.*
- GREAT BATTERY LIFE AND FASTER CHARGING—Enjoy a smartwatch with all-day, 18-hour battery life* from sunup to sundown. Then charge up to twice as fast as SE 2* and get up to 8 hours of battery in just 15 minutes.*
If the watch is updated but no reading appears
- Confirm that both the iPhone and Apple Watch—not just one—are updated.
- Check the iPhone Health app, not only the Watch app, at Browse → Respiratory.
- Verify that the watch is the affected U.S. configuration of a Series 9, Series 10, or Ultra 2.
- Make sure the watch is paired to the iPhone you are checking.
- Complete any pending setup, then close and reopen Health.
- Restart both devices and check again.
- If the feature remains absent, contact Apple Support with the watch’s exact model and sales region.
What to check when buying a used watch
Used listings often mix pre-ban U.S. watches, post-ban U.S. watches, international models, and service replacements. A listing title or stock photograph is not proof that Blood Oxygen works.
- Exact model: Series 9, Series 10, or Ultra 2.
- Sales region and original configuration.
- Whether Blood Oxygen currently appears in Health → Respiratory.
- Activation Lock status.
- Battery health and a usable return policy.
A seller should be able to demonstrate the feature on the actual watch and paired iPhone. Treat Blood Oxygen as a secondary buying factor, since Apple positions it as a wellness capability rather than a medical instrument.
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![Apple Watch Series 11 [GPS 42mm] Smartwatch with Jet Black Aluminum Case with Black Sport Band - S/M. Sleep Score, Fitness Tracker, Health Monitoring, Always-On Display, Water Resistant](https://m.media-amazon.com/images/I/41s72HIk5TL._SL160_.jpg)
- A FULL-FEATURED HEALTH TRACKER—Apple Watch Series 11 gives you invaluable insights about your body, right from your wrist. Take an ECG anytime* and get alerts for a high and low heart rate or an irregular rhythm*—so you can stay closer to your heart. You can also view your overnight health tracking metrics with the Vitals app* and be notified of possible sleep apnea.*
- KNOW YOUR SLEEP SCORE—With advanced sleep tracking, Series 11 gives you a daily sleep score. It’s an easy way to help measure and understand the quality of your sleep, so you can make it more restorative.
- GET HYPERTENSION NOTIFICATIONS—Did you know that Series 11 can spot signs of chronic high blood pressure? By analyzing how your blood vessels respond to beats of the heart, it can notify you of possible hypertension.*
- SAFETY FEATURES—A smartwatch that puts your safety first. Series 11 can detect a hard fall or severe car crash, automatically help connect you with emergency services, and notify your emergency contacts.* Check In can automatically notify a loved one when you’ve arrived at your destination.
- A POWERFUL FITNESS TRACKER—With advanced metrics and motivating features like Pacer, Heart Rate Zones, training load, and Workout Buddy powered by Apple Intelligence from your nearby iPhone*—Series 11 is made to help everyone stay active, from runners and hikers to strength-training enthusiasts.
Is Apple Watch Blood Oxygen medical-grade?
No. Apple describes Blood Oxygen as a general-wellness feature. Readings can be affected by fit, motion, circulation, temperature, and other factors. Do not use an Apple Watch reading to diagnose or rule out a condition; use an appropriate clinical device and seek professional care when medically necessary.
Apple’s newer health-feature materials preserve that wellness positioning: Series 11 and Ultra 3.
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