Currently, there is no official "portable" version of the Proton Mail desktop app designed to run from a USB drive without installation. Proton's official desktop application requires installation on Windows 10+, macOS 10.15+, or Linux and is primarily available to users with a paid plan (though free users can access a 14-day trial).
Q: What about the Android "portable" app?
A: Android doesn't have a "portable" concept like Windows. Use the official Proton Mail Android app and a secondary phone. proton mail desktop app portable
Progressive Web App (PWA): You can "install" Proton Mail as a PWA through Chrome or Edge. While this creates a desktop-like experience, it is tied to the host browser and is not natively portable. Currently, there is no official "portable" version of
Background and Related Work: