Best European alternatives to Proton Calendar in 2026

Tuta Calendar is a privacy-focused encrypted calendar integrated with the Tuta secure email service. It offers end-to-end encryption for all events and data, ensuring no third party can access your schedule.

EteSync provides end-to-end encrypted, privacy-focused synchronization for contacts, calendars, and tasks. All data is encrypted client-side before leaving your device, and both client and server code are fully open source. Available as paid hosted service or self-hosted.

Nextcloud Calendar

Scheduling

EU Mentions

Nextcloud Calendar is an open-source CalDAV-based calendar app integrated into the Nextcloud platform. It allows users to manage personal and shared calendars, schedule events, and sync across devices while keeping data self-hosted.