Masimo Sues U.S. Customs Over Apple Watch Blood Oxygen Feature, Demands Ban Reinstate

In a new twist to its ongoing feud with Apple, medical device company Masimo has taken legal action against U.S.

Customs and Border Protection (CBP), challenging the agency’s decision to lift the import ban on Apple Watch models featuring the Blood Oxygen monitoring tool. Masimo wants the ban reinstated, claiming that CBP exceeded its authority and violated procedural protocols when it allowed the reactivation of this feature.

For context, Apple’s recent iOS 18.6.1 update included a workaround that lets the Apple Watch still perform Blood Oxygen monitoring when paired with an iPhone, circumventing previous restrictions. Masimo is not pleased with this workaround, which could potentially infringe upon its pulse oximetry patents.

The legal battle between Apple and Masimo dates back to December 2023 when the U.S. International Trade Commission (ITC) ruled that Apple’s use of certain technology violated Masimo’s patents, specifically relating to pulse oximetry. As a result, an import ban was imposed on Apple Watch Series 9 and Apple Watch Ultra 2 models that incorporated the Blood Oxygen feature. To stay in compliance, Apple disabled the feature temporarily through a software update, but soon after, it quietly re-enabled the functionality with a workaround that bypassed the ITC ruling.

Masimo has now filed for a temporary restraining order and a preliminary injunction to block the CBP’s ruling that allowed Apple to bypass the ban. The company argues that the continued reactivation of the feature puts it at a significant competitive disadvantage in the U.S. market, and if left unchallenged, it would cause irreparable harm. Moreover, Masimo claims that CBP reversed its decision without providing justification or offering Masimo an opportunity to respond, which they contend undermines their legal protections.

The core issue stems from a ruling made by CBP on August 1, 2025, which permitted Apple to import devices that, when paired with iPhones in the U.S., would perform the same function that the ITC had previously determined violated Masimo’s patents. Masimo was only made aware of this shift in policy on August 14, 2025, when Apple made the announcement to reactivate the Blood Oxygen feature. The lawsuit could have significant implications, not only for the tech industry but for the medical device sector as well, highlighting the complex intersection of patent law, regulatory decisions, and innovation.

As the legal battle unfolds, the outcome could influence how companies navigate patent rights and product features in the future. We’ll continue to monitor this case closely and bring you updates as the story develops.