Masimo sues US Customs over Apple Watch blood oxygen return

Last week, when Apple announced the release of a “redesigned Blood Oxygen feature” to the Apple Watch, many figured Masimo (who had been suing Apple over patents related to the feature), would look for a way to fight back. Today, the company did just that and filed a new lawsuit. But this time, it’s against the US Customs and Border Protection. Here’s why.

A bit of background

When Apple released the Blood Oxygen feature on the Apple Watch, medical device maker Masimo sued over alleged patent infringement.

Over the years, the lawsuit dragged on and came to a head with an import ban in December 2023, which prohibited Apple from selling Apple Watch models with the Blood Oxygen feature in the U.S.

Since then, after halting sales for a few days, Apple had been selling the Apple Watch Series 9 and Apple Watch Ultra 2 without the Blood Oxygen feature, although it didn’t remove the hardware. Rather, the feature was disabled via software.

Last Thursday, Apple announced a “redesigned Blood Oxygen feature,” which calculates the Blood Oxygen on the iPhone, rather than on the Watch.

So Masimo is suing again?

Yes. Masimo filed a new complaint in the US District Court for the District of Columbia on Wednesday.

The company says US Customs and Border Protection (CBP) overstepped its authority and violated due process when it reversed its earlier decision on August 1 and allowed Apple to restore the feature. Moreover, Masimo says it found out about the decision when Apple publicly announced the return of the feature:

“It has now come to light that CBP thereafter reversed itself without any meaningful justification, without any material change in circumstances, and without any notice to Masimo, let alone an opportunity for Masimo to be heard. CBP changed its position on Apple’s watch-plus-iPhone redesign through an ex parte proceeding. Specifically, on August 1, 2025, CBP issued an 3 ex parte ruling permitting Apple to import devices that, when used with iPhones already in the United States, perform the same functionality that the ITC found to infringe Masimo’s patents. Masimo only discovered this ruling on Thursday, August 14, 2025, when Apple publicly announced it would be reintroducing the pulse oximetry functionality through a software update.”

The company is now asking the court for a temporary restraining order and preliminary injunction to block the CBP’s decision, and reinstate the original ruling that “determined that Apple’s redesigned watches could be imported only to the extent the infringing functionality was completely disabled.”

As reported by Bloomberg Law, Masimo says the following in its supporting brief:

“Each passing day that this unlawful ruling remains in effect irreparably deprives Masimo of its right to be free from unfair trade practices and to preserve its competitive standing in the U.S. marketplace.”

Masimo further argues that CBP’s move “effectively nullified” the ITC’s exclusion order against Apple. Apple’s appeal of that ban is still pending before the Federal Circuit.

Do you think Masimo will manage to get a new ban on the Apple Watch Blood Oxygen measurement? Let us know in the comments.

Limited time Apple Watch deals on Amazon

Keep track of your essentials with the Apple AirTag 4 Pack, the ultimate tracking solution for your belongings. With over 5,972 ratings and a stellar 4.7-star average, this product has quickly become a customer favorite. Over 10,000 units were purchased in the past month, solidifying its status as a highly rated Amazon Choice product.

For just $79.98, you can enjoy peace of mind knowing your items are always within reach. Order now for only $79.98 at Amazon!

Help Power Techcratic’s Future – Scan To Support

If Techcratic’s content and insights have helped you, consider giving back by supporting the platform with crypto. Every contribution makes a difference, whether it’s for high-quality content, server maintenance, or future updates. Techcratic is constantly evolving, and your support helps drive that progress.

As a solo operator who wears all the hats, creating content, managing the tech, and running the site, your support allows me to stay focused on delivering valuable resources. Your support keeps everything running smoothly and enables me to continue creating the content you love. I’m deeply grateful for your support, it truly means the world to me! Thank you!