Recording Law for Voiceprints & Biometric Data in Montana

Montana’s wiretap statute, Mont. Code Ann. § 45-8-213, does not ban recording conversations outright. It only makes it unlawful to record a conversation using a "hidden electronic or mechanical device" without the knowledge of all parties. If your recording device is visible—like a body-worn camera or smart glasses—you are not using a hidden device, so the statute does not apply. The law also provides a simple way to cure any knowledge issue if the device is hidden: under §45-8-213(2)(a)(iii), if one person provides the warning, either party may record, satisfying the statute. This means you can openly record conversations in Montana without needing anyone’s consent, as long as the device is not hidden. The statute’s hidden-device gate is the only procedural threshold; it does not turn on whether the conversation is private or where it occurs.

The key question under §45-8-213 is whether the device is hidden, not whether the conversation is private or where it occurs. The statute specifically targets recordings made with a device that is not visible to the parties. If the device is clearly visible—like a phone held in your hand or a camera worn on your chest—it is not hidden, and the law does not restrict your recording. The statute does not require a reasonable expectation of privacy in the conversation itself. The only gate is the manner of recording: hidden vs. open. For example, if you wear smart glasses in a public meeting and the glasses are clearly visible, you are not using a hidden device, so the wiretap statute does not apply. The statute includes an exception in §45-8-213(2)(a)(i) for public officials acting in official duty when they are the ones recording.

Montana sits within the Ninth Circuit, which has recognized a First Amendment right to record police officers performing their official duties in public. In Fordyce v. City of Seattle, 55 F.3d 436 (9th Cir. 1995), and Askins v. U.S. Dep't of Homeland Security, 899 F.3d 1035, 1044 (9th Cir. 2018), the Ninth Circuit held that the First Amendment protects the right to photograph and record matters of public interest, including law enforcement officers engaged in official duties in public places. This means you can record police officers in public in Montana without violating the wiretap statute, as long as your device is not hidden. There is no separate Montana statute that restricts citizens from recording police, and the wiretap law’s hidden-device requirement does not apply to openly worn devices.

Montana’s privacy law, the Montana Consumer Data Privacy Act (MCDPA), treats biometric data—including voiceprints—as a category of "sensitive data." Under § 30-14-2812(2)(b), a business cannot process sensitive data without the consumer’s consent. However, the MCDPA excludes from the definition of "biometric data" any "audio or video recording" unless that data is generated to identify a specific individual. This means that simply recording a conversation is not biometric data processing under the MCDPA. The law only applies if you extract a voiceprint from the recording for the purpose of identifying a specific person. If your processing of voice data involves generating a voiceprint for identification, you must obtain consent from the individual whose data is being processed.

Montana’s wiretap law does not have a home-specific carve-out. However, a separate statute, § 45-5-223, makes it unlawful to secretly record someone inside a private residence without their knowledge. This provision is aimed at covert surveillance, not open recording. If you are openly recording with a visible device, even inside someone’s home, this statute does not apply. The key distinction under §45-5-223 is whether the recording is surreptitious, not the location. For example, if you wear smart glasses in a client’s office and the glasses are clearly visible, you are not using a hidden device, so the wiretap statute does not apply.

Imagine you are speaking with a neighbor in a public park. You wear smart glasses that are clearly visible to the neighbor. The glasses record the conversation. Because the device is not hidden, Montana’s wiretap statute does not apply. The recording is lawful. Now imagine the same meeting, but you hide a small audio recorder in your pocket. The device is hidden, so the statute applies. However, under §45-8-213(2)(a)(iii), if you or the neighbor provides the warning before it starts, the statute’s knowledge requirement is satisfied, and the recording becomes lawful. If you later process the recording to generate a voiceprint for identification purposes, you must obtain the neighbor’s consent under the Montana Consumer Data Privacy Act.

Even when a recording device is openly visible, Montana’s constitutional right of individual privacy (Article II, Section 10) may support a civil invasion-of-privacy claim in places where a person has a genuine expectation of privacy, despite the criminal statute’s hidden-device gate never being triggered. This constitutional layer is separate from the wiretap statute and has not been tested in Montana courts. For example, recording in a public restroom stall, a changing room, or a private office with the door closed could implicate this constitutional concern, even if the device is visible. Because this risk is fact-specific and unsettled, treat capture in such secluded sub-spaces within nominally public locations as requiring an affirmative announcement of recording or attorney override before permitting capture, regardless of device visibility.