Proton Mail AlternativesOnly apps categorised as Calendar Apps

The best Calendar alternative to Proton Mail is Tuta Mail, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 50 alternatives to Proton Mail and 12 are Calendar Apps so hopefully you can find a suitable replacement. Other interesting Calendar App alternatives to Proton Mail are Posteo, mailbox, Mailfence and Fastmail.

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Proton Mail alternatives are mainly Calendar Apps, but if you're looking for WebMail Providers or Email Clients you can filter on that. Other popular filters include Free, Open Source and Self-Hosted. These are just examples - use the filter bar below to find more specific alternatives to Proton Mail.
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Alternatives list

  1. Tuta Mail icon
     515 likes
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    Offers comprehensive encryption for email, calendar, and contacts with zero personal info required. Built on open source, install via Play Store, F-Droid, or APK, with Tor and VPN support. Both free and paid plans; utilizes quantum-resistant encryption ensuring privacy-focused, anonymous usage.

    100 Tuta Mail alternatives

    Cost / License

    • Freemium (Subscription)
    • Open Source

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • iPad
    • Flathub
    • F-Droid
     
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    10
    153
    Comments about Tuta Mail as an Alternative to Proton Mail
    Comment summary: Tutanota is praised for its affordability and transparency, offering end-to-end encryption and a generous free storage plan that appeals to budget-conscious users. However, users note a wait period for account activation. It is considered user-friendly, though Proton Mail is seen as more secure but pricier. Tutanota encrypts titles and contacts, which some believe gives it an edge in privacy. Overall, it functions well on secure browsers and maintains a straightforward encryption model.
    Top Positive Comment
    Advik
    3

    Tutanota is end-to-end encrypted, as well offers 1 GB mail storage on free plan. The pro plans are cheap compared to protonmail, so it's better for low budget users

    Conner Vieira
    Positive
    -2

    Tutanota has historically been a lot more transparent, and arguably has been more honest about issues and plans

    Ada Byron
    Positive
    1

    I use both, ProtonMail is more secure but also more expensive and not as user-friendly. You cannot beat the price of Tutanota for service they provide.

    Show more comments
    3 of 10 comments
    Proton Mail Icon
    Tuta Mail icon
    • Almost everyone thinks Tuta Mail is a great Proton Mail alternative.

    • Tuta Mail is the most popular Web-based, Windows, Android & Mac alternative to Proton Mail.

    • Tuta Mail is the most popular Open Source & free alternative to Proton Mail.

    • Tuta Mail is Freemium and Open SourceProton Mail is also Freemium and Open Source
    • Tuta Mail is LightweightProton Mail is not according to our users
  2. Posteo icon
     83 likes
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    Web- and IMAP-based email service. 2GB cost 1€/month. Information is hosted on encrypted hard drives. Electricity from renewable resources is used.

    74 Posteo alternatives

    Cost / License

    • Subscription
    • Open Source

    Platforms

    • Online
     
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    1
    26
    Comments about Posteo as an Alternative to Proton Mail
    John Fastman
    Positive
    2

    Posteo could be a good Protonmail alternative. It offers email encryption in a similar way: Posteo's people, government surveillance and successful hackers won't get into your email content. It also offers a calendar feature, which protonmail users have been crying out for for years.

    Proton Mail Icon
    Posteo icon
    • Almost everyone thinks Posteo is a great Proton Mail alternative.

    • Posteo is the most popular commercial alternative to Proton Mail.

    • Posteo is Paid and Open SourceProton Mail is Freemium and Open Source
    • Posteo is Security-focusedProton Mail is not according to our users
  3. mailbox icon
     74 likes
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    E-mail inbox, online office, cloud storage, and video conferencing. Business or personal plans. From 1 € /month (1.10 USD).

    82 mailbox alternatives

    Cost / License

    • Subscription
    • Proprietary

    Platforms

    • Online
     
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    1
    19
    Comments about mailbox as an Alternative to Proton Mail
    John Fastman
    Positive
    2

    Mailbox.org is a partial replacement for Protonmail. It offers a fully functional email solution (email, calendar, contacts), but with the added benefits of PGP encryption support (you can handle the keys or let them do it). It also allows you to send links to people who don't use PGP if you want to send private messages. For the encryption, it's a bit like Protonmail. For everything else, it's like a privacy-respecing Gmail alternative.

    Proton Mail Icon
    mailbox icon
    • Almost everyone thinks mailbox is a great Proton Mail alternative.

    • mailbox is Paid and ProprietaryProton Mail is Freemium and Open Source
    • mailbox is Security-focusedProton Mail is not according to our users
  4. Mailfence icon
     62 likes
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    This secure email platform offers end-to-end encryption, a comprehensive suite with Calendar and Documents. Mailfence is inter-operable with OpenPGP services, features digital signatures, provides keystores, and available as a PWA for mobile independence while ensuring no ads, trackers, or surveillance.

    71 Mailfence alternatives

    Cost / License

    • Freemium (Subscription)
    • Proprietary

    Platforms

    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
     
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    7
    25
    Comments about Mailfence as an Alternative to Proton Mail
    Top Positive Comment
    PhmNguynHngThnh
    5

    Mailfence offers more functionality than Proton mail with Calendar, Document, Chat, and Group functionality. Moreover, the price is much lower than other competitors.

    Top Negative Comment
    Guest
    2

    Costs money to use with 3rd party programs.

    Review by a new / low-activity user.
    Guest
    Positive
    1

    because its free and don't need any pay and don't want phone number to sign in

    Review by a new / low-activity user.
    Show more comments
    3 of 7 comments
    Proton Mail Icon
    Mailfence icon
    • Most users think Mailfence is a great Proton Mail alternative.

    • Mailfence is the most popular Android Tablet alternative to Proton Mail.

    • Mailfence is Freemium and ProprietaryProton Mail is Freemium and Open Source
  5. Fastmail icon
     75 likes
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    Fastmail offers secure email hosting with comprehensive webmail services, including IMAP, POP, and SMTP protocols. It supports file sharing, shared folders, large mailboxes, instant messaging, and is compatible with popular email programs. Excellent for businesses with compliance features.

    72 Fastmail alternatives

    Cost / License

    • Subscription
    • Proprietary

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Flathub
    • Flatpak
     
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    6
  6. Vivaldi Mail icon
     34 likes
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    Vivaldi Mail is a free email service with no ads and no strings attached developed by Vivaldi Technologies. It also offers contacts and calendar features, search capabilities, folders management, WEB/POP/IMAP access, 10GB of storage capacity, 20 MB of maximum attachment size...

    101 Vivaldi Mail alternatives

    Cost / License

    • Free
    • Proprietary

    Platforms

    • Online
    • Vivaldi
     
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    1
    7
    Comments about Vivaldi Mail as an Alternative to Proton Mail
    John Fastman
    Positive
    0

    Vivaldi mail offers PGP-based email encryption, similar to Protonmail. But the web client is much less well developed. However, unlike Protonmail (at the time of writing), they allow you to import your own PGP keys, which is nice (a feature Protonmail users have been demanding for years).

    Proton Mail Icon
    Vivaldi Mail icon
    • Most users think Vivaldi Mail is a great Proton Mail alternative.

    • Vivaldi Mail is Free and ProprietaryProton Mail is Freemium and Open Source
  7. Copy a direct link to this comment to your clipboard

    Privacy-focused Swiss email system provides 20 GB free storage, supports custom domains and unlimited storage, syncs contacts and calendars, is ad-free, and is part of a secure productivity suite used by over a million users across Europe on all devices.

    Cost / License

    • Freemium (Subscription)
    • Open Source

    Platforms

    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • F-Droid
     
  8. Kolab Now icon
     42 likes
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    Kolab Now provides a suite of intuitive apps in a user friendly environment to make your day to day online comms easier, smarter and most importantly; secure.

    78 Kolab Now alternatives

    Cost / License

    • Subscription
    • Open Source

    Platforms

    • Online
    • Software as a Service (SaaS)
    • DAVx5
     
  9. Mailture icon
     Like
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    Mailture, a secure, business-oriented email service, is made to cater to all your emailing needs. With top-notch collaboration and communication features, Mailture offers much more than your usual inbox.

    Cost / License

    • Subscription
    • Proprietary

    Alerts

    • Discontinued

    Platforms

    • Software as a Service (SaaS)
     
  10. VFEmail icon
     6 likes
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    Free email with privacy and security.

    Cost / License

    • Freemium (Subscription)
    • Proprietary

    Platforms

    • Online
     
  11. mail2world icon
     2 likes
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    the free email that has everyone talking!.

    Cost / License

    • Freemium (Subscription)
    • Proprietary

    Platforms

    • Online
     
12 of 12 Proton Mail alternatives