Apple Watch Blood Oxygen Monitoring Returns To The U.S. After 18-Month Ban With Clever Redesign

For nearly two years, Apple Watch users in the United States lived without one of the most popular health features: blood oxygen monitoring. Today, Apple has officially reintroduced the function through a software workaround that sidesteps the long-running patent battle with health tech company Masimo.

A Quick Refresher On Why It Disappeared

Back in December 2023, the U.S. International Trade Commission ruled that Apple had violated Masimo’s patents related to pulse oximetry technology. That ruling led to an import ban that forced Apple to temporarily halt sales of its latest watches. To resume business, Apple stripped the Blood Oxygen app from new Apple Watch Series 9 and Ultra 2 units sold in the U.S., leaving customers with hardware capable of readings but disabled by software.

The ban remained in place well into 2024, and even the Apple Watch Series 10 launched last year without the feature in America. The rest of the world continued enjoying blood oxygen monitoring, while U.S. buyers were stuck with a crippled version.

The Workaround: Shift The Processing To iPhone

Apple’s new solution, released as part of iOS 18.6.1 and watchOS 11.6.1, cleverly moves the calculation step from the Watch to the iPhone. The watch’s sensors still collect raw light data, but the paired iPhone now does the heavy lifting of translating that into a blood oxygen reading.

What this means in practice:

• You initiate a measurement using the Blood Oxygen app on the Apple Watch.
• The watch captures the raw sensor data.
• Your iPhone processes the information and displays the results in the Health app under the Respiratory section.
• The results are no longer viewable on the Watch itself.

This redesign satisfied U.S. Customs, which recently ruled that Apple may import and sell watches using this modified approach.

Which Models Regain The Feature

The update is available for:

• Apple Watch Series 9 (U.S. units missing the original feature)
• Apple Watch Series 10
• Apple Watch Ultra 2

Importantly, older devices like Series 7 or 8 may not see the same fix unless they were replacement units with the feature disabled. Watches purchased outside the U.S., or earlier models that shipped before the ban, keep their original on-device blood oxygen processing and are unaffected.

Background Monitoring Still Works

Even with the shift to iPhone, Apple has preserved background blood oxygen checks. That means your watch can collect data passively during sleep or throughout the day, and then send it to the iPhone for analysis. It’s less convenient than instant wrist-based feedback, but it maintains continuity in your Health app records.

Why Did This Take So Long?

Many users are asking why Apple didn’t launch this workaround immediately when the ban began. The reality is that software changes involving patent disputes must be cleared by regulators. Apple could not simply flip a switch without approval. A recent U.S. Customs ruling gave the green light, allowing Apple to finally move forward.

The Patent Timeline

The Masimo patents at the heart of the dispute expire in 2028. At that point, Apple could theoretically restore full on-device calculations for U.S. models. Until then, it’s likely the iPhone-based workaround will remain in place, though Apple may continue refining the experience.

Early Reactions From Users

The update is rolling out now, and reactions are mixed:

• Some users report the feature reactivates after running an ECG and then opening the Blood Oxygen app.
• Others note that it can take several hours or even overnight for the system to fully enable.
• A few have experienced glitches where the app still says “not available,” though Apple Support suggests leaving the watch on its charger may help trigger activation.

What It Means For Health Tracking

Blood oxygen readings are critical for people with conditions like asthma, sleep apnea, and heart disease, and they also play a role in detecting early illness or monitoring recovery. Restoring this feature, even in a modified form, fills a major gap for Apple Watch users who had been left behind.

The data may not be available instantly on your wrist, but for many, having continuous readings synced to the Health app is more than enough. In fact, some speculate this approach may even help battery life since processing is offloaded to the iPhone.

Looking Ahead

Apple continues its appeal of the ITC’s decision and hopes for a full reversal. But with this workaround, the company has bought itself time and restored functionality to millions of users in the meantime. The timing is also notable: September is around the corner, and new Apple Watch models are expected. With the legal cloud partially lifted, Apple can market its watches in the U.S. without disclaimers about missing health features.

For now, American users can finally breathe a little easier knowing their Apple Watch can measure how well they breathe too.