Blood Oxygen not available on Apple Watch Ultra 2 after watchOS 18.6.1 update

I did all the updates and still couldn't get O2 measurement until I ran the EKG. Of course this is ridiculous since it's not mentioned anywhere to do this. With as much as apple software engineers get paid they could do a LOT better

For US-imported Ultra 2 with model numbers ending with LL/A, the app and sensor are available on the Watch, and continue to function as they have.

For US-imported Ultra 2 model numbers ending with LW/A and with iOS 18.6.1 and watchOS 11.6.1, the pulse oximeter function is now in the iPhone, in the Respiratory part of Health app.

Identify your Apple Watch - Apple Support

Apple Watch models sold in other countries and regions are not affected by this, and the pulse oximetry feature and app remain available in the Watch.

DeanMBP wrote:

Hmmmmm .... I bought my Ultra 2 (in the US) AFTER it had been disabled. Mine ends in LW/A. Can I take a manual reading from the health app?

I’m concerned. Confusion can be one of the signs of hypoxia. 😉

As for your question, did you update iOS and watchOS, and try it?

Thanks! I understand. I got that screenshot from:a MacRumors article and misinterpreted its context.

Instead, I’ll cite a reference you offered in a different thread:

An update on Blood Oxygen for Apple Watch in the U.S. - Apple

Sorry for the confusion.

KiltedTim wrote:

That screen shot is not accurate. Blood oxygen results are not visible on the watch. They will only be visible in the health app on the phone.

A clarification to the correction: the reading will not be visible on Watch with the Watch models ending LW/A. The display is only on iPhone.

With Watch models ending LL/A, the pulse oximetry display remains on Watch.

DeanMBP wrote:

Yes, I had updated both before it posted the original post. I don’t see any change at all.

If you are looking in the Respiratory section of Health app on the iPhone — Health app on the iPhone, and not on Watch — and are running iOS 18.6.1 and watchOS 11.6.1, then contact Apple. There is no display on the Watch.

I updated my iPhone 16 Pro (iOS 18.6.1), then my Apple Watch Series 10 U.S. model (watchOS 11.6.1) previously blocked for Blood Oxygen use

At first, the Apple Watch blood oxygen app still had the old not available message.

Either because it took time for the iPhone to sync the new blood oxygen app to the Apple Watch, or because I manually power cycled both the iPhone and Apple Watch, but eventually the Apple Watch blood oxygen app allowed me to take a measurement.

The Blood Oxygen app would NOT show me the value on my my Apple Watch.

I had to go iPhone -> Health app -> Respiration -> Blood Oxygen to see my reading.

I assume you have to read on the iPhone because Apple is walking a thin line to avoid patent violations.

DeanMBP wrote:

Looks like I’ll have to give Apple a shot. I’ve done all of that. Looked in the health app and the respiratory section, it shows my old data, but nothing new. How do you trigger a new reading?

Opening the Respiratory section of Health on the paired iPhone should be enough.

I’d try an un-pair and re-pair, as that’ll probably be at the top of the Apple troubleshooting when you call them.

Well I feel silly! Apparently, because it wasn’t available. I had deleted the app from my watch. It was in the cloud! Re-downloaded it and now it is available. You will get a reading if you do the ECG. But results only show in the health app.

The Blood Oxygen app is available on Apple Watch Series 6 and later, including Apple Watch SE (2022), Apple Watch Ultra, and Apple Watch Ultra 2. It is not supported on earlier models such as Series 5, Series 4, or the original Apple Watch SE. If you have a compatible model and still cannot use the feature after updating, you may be affected by the bug described below.

How to fix Blood Oxygen not working on watchOS 11.6.1

Zollo’s method uses other health sensors on the Apple Watch to “wake” the Blood Oxygen function:

• Open the Heart Rate app on your Apple Watch.
• Take a manual heart rate reading.
• Open the ECG app.
• Perform a full ECG reading.

After completing these steps, the Blood Oxygen app may reappear as active, allowing you to take measurements normally.

Why this Blood Oxygen fix might work

The exact reason this sequence works is unclear, but it likely forces watchOS to refresh sensor permissions and availability, triggering the Blood Oxygen feature to become accessible again.

Once watchOS and iOS are updated:

That screen shot is not accurate. Blood oxygen results are not visible on the watch. They will only be visible in the health app on the phone.