📅 Calendar Privacy ★★★★★
Proton Calendar
End-to-end encrypted calendar
Overview
Proton Calendar encrypts event details client-side—Proton cannot read your schedule.
Part of Proton Mail/Drive/VPN ecosystem for staged Google Workspace exit.
Swiss-hosted with shared calendars and mobile apps expanding since 2024.
Scores
Privacy 5/5
Ease of use 4/5
Features 3/5
Value 4/5
Google Calendar — comparison
Unlike Google Calendar, events are E2EE—not fodder for ads or AI. Official help states that CalDAV is not supported; external calendars are read-only URL subscriptions.
Pros
- ✓ E2EE for event content (zero-access)
- ✓ Unified Proton ecosystem experience
- ✓ Strong Swiss privacy protections
- ✓ Clean web and mobile UI
Cons & caveats
- − No CalDAV support (official help); external calendars are read-only URL subscriptions
- − Free plan includes 3 personal calendars (up to 25 on Mail Plus or Unlimited)
- − Weaker external integrations than Google Calendar
Best for
- Proton Mail users
- E2EE priority
- First step leaving Google Workspace
Not ideal for
- CalDAV-native desktop workflows
- Large team shared calendars on free tier
Specs
- Pricing
- Free + paid — Official (confirmed 2026-11-11): the free plan includes 3 personal calendars. Mail Plus or Proton Unlimited allows up to 25 personal calendars. You can subscribe to up to 3 external calendars on the free plan, or up to 25 calendars on a paid plan (personal or not). External calendars are read-only. Proton Calendar does not support CalDAV, so there is no two-way sync with external calendar apps (official help). There is no cap on the total number of events (https://proton.me/ja/pricing). You can import up to 15,000 events at a time (https://proton.me/ja/support/how-to-import-calendar-to-proton-calendar). Recurring events are limited to 49 repeats (https://proton.me/support/protoncalendar-create-update-and-delete-recurring-events). Sources for calendar counts, external calendars, and CalDAV: https://proton.me/mail/pricing, https://proton.me/support/calendar, and https://proton.me/support/subscribe-to-external-calendar
- Difficulty
- Easy
- Data location
- Switzerland (Proton AG); zero-access—servers hold ciphertext only.
- Platforms
- Web · Android · iOS
Zero-access暗号化Proton Mail統合共有カレンダー
Migration from Google Calendar
- 1 Export Google Calendar as .ics
- 2 Import .ics in Proton Calendar web
- 3 Link with Proton Mail account
- 4 Install mobile apps and configure notifications
Setup steps
- 1 Create Proton account at proton.me
- 2 Open Proton Calendar and complete setup
- 3 Import Google .ics export
- 4 Install Android/iOS app and verify sync