As a dedicated Proton user, I greatly value the privacy and security that Proton services offer. However, the inability to integrate Proton Calendar with native applications like Apple Calendar presents a significant limitation in my daily workflow.

I propose enhancing the Proton Bridge to support CalDAV, enabling seamless synchronization of Proton Calendar events with desktop calendar applications such as Apple Calendar and Thunderbird. This integration would allow users to view and manage their Proton Calendar alongside other calendars in their preferred native applications, improving usability and efficiency.

Currently, Proton Bridge facilitates synchronization for emails and contacts via IMAP/SMTP and CardDAV, respectively. Extending this functionality to include CalDAV for calendar synchronization would provide a more comprehensive solution for users seeking to consolidate their communications and scheduling within Proton’s secure ecosystem.

This feature has been a recurring request within the Proton community, as evidenced by discussions and suggestions on the UserVoice platform. Implementing CalDAV support through Proton Bridge would address these user needs and enhance the overall appeal of Proton services.

I kindly urge the Proton team to consider this enhancement, which would significantly improve the user experience for those who rely on native calendar applications in their daily routines.

I can share calendars from Proton Calendar to Thunderbird as read-only but I cannot add/amend events from Thunderbird to Proton. This is a nuisance since invites arrive in email via Thunderbird. Of course if I accept them then they are added to a local calendar, but then I can't see them in my Proton calendar.
My rather convoluted work around is to copy the event from my local Thunderbird calendar, then paste into a plain text file (using MacOS, I use TextEdit), and save with a .ics file name. I can then import this into my Proton calendar accessed with my browser. This is fine for a few events but a right nuisance for all of my calendars.

Very critical !

Has Proton even responded to this feature request?

Very critical

Please get this fixed - really not an option using Proton mail app on windows, as i do not support localization, so for me Thunderbird is the thing - but then again, no calendar !

How can this take so long ... ?

Please, please, please! A CalDAV/CardDAV bridge would make Proton such an easier sell to customers. I’ve already moved my contacts to a self-hosted solution and I really don’t feel like doing the same for my calendar seeing as I’m already paying for Proton Calendar. Please put this on the roadmap!

Either make bridge work so that calendars form multiple mail clients can all be in one place, or allow additional IMAP accounts to proton mail, so mail and calendars can all be in one place (preferred option, but I'll take whichever one I can get!).

I really need this functionality. It's very frustrating I can't sync calendars of multiple accounts right now. Please work on this feature!

Can we get an update on when this feature will come?

This is such an important feature to have. I want my calendar and email all in one app like Outlook or Thunderbird. Right now, since i have some non-proton emails, I have to have Thunderbird (for non-Proton email) and Proton apps (to make sure I get calendar alerts) open simultaneously.

For work I need to be able to use one calendar client where I can manage both proton but also other calendars. Both to edit and to view which is not possible now.
Please support this!

I need to be able to access and change calendars from outlook or ical to be able to work with multiple accounts (incl. work)

Still would be great after 4 years.

I just paid very good money for an annual subscription for both me and my partner, only to find out I can't sync my calendar between my email client on my computers and my Proton account. This is a very large functionality gap I would like addressed.

A critical feature, which in my case is the only real roadblock to be able to fully migrate all my calendars to Proton.

I migrated all my emails to Proton about a month ago, assuming that the calendar and Contacts would be synchronized with Outlook, like the emails. What a mistake! I am very disappointed. This is critical; I constantly have to switch from one application to another. I am seriously considering going back to Outlook.

It would be nice to have this reflected on the roadmap, since it is unlikely to be deemed unnecessary.

Proton Mail Bridge can be turned into Proton Bridge and include the following features to provide complete local accessibility.
- Mail via IMAP & SMTP
- Contacts via CardDAV
- Calendar via CalDAV
- Drive via WebDAV

Mail is already part of the bridge, and it would continue to be the core functionality of the bridge. Other features should be toggles.

Drive can be too large to sync for some devices, and may not be desirable. It can be implemented as a storage for uploading files larger than 25 MB and won't fit as an attachments. Uploading to drive would automatically generate a share link which can be pasted into the email.

Thunderbird does support WebDAV storages such as NextCloud via an extension, https://addons.thunderbird.net/en-CA/thunderbird/addon/filelink-provider-for-owncloud/ .