K-9 Mail Alternatives for Android

There are many alternatives to K-9 Mail for Android if you are looking for a replacement. The best Android alternative is Thunderbird, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 25 alternatives to K-9 Mail and many of them are available for Android so hopefully you can find a suitable replacement. Other interesting Android alternatives to K-9 Mail are FairEmail, Microsoft Outlook, Spark Mail and Canary Mail.

filter to find the best alternatives

K-9 Mail alternatives are mainly Email Clients, but if you're looking for Calendar Apps or Contact Managers you can filter on that. Other popular filters include Android + Open Source. These are just examples - use the filter bar below to find more specific alternatives to K-9 Mail.
K-9 Mail iconK-9 Mail
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K-9 is an open source email client for Android with multi-folder sync, email signatures, Bcc-to-self, return-address configuration, keyboard shortcuts, Exchange Support, message flagging, IMAP deletes, saving attachments,...

More about K-9 Mail
K-9 Mail alternatives page was last updated Mar 13, 2025
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  1. Thunderbird icon
     2467 likes
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    Cross-platform email client supporting multiple identities, chat, and strong filtering. Extend functionality with add-ons like RSS/Atom feed readers and PGP support.

    85 Thunderbird alternatives

    License model

    • FreeOpen Source

    Application types

    Country of Origin

    • US flagUnited States

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • BSD
    • AppImageHub
    • Snapcraft
    • Flathub
    • PortableApps.com
    • F-Droid
    • Haiku
    • Homebrew
    • Chocolatey

    Properties

    1.  Customizable
    2.  Intuitive Interface
    3.  Privacy focused

    Features

    1.  Extensible by Plugins/Extensions
    2.  Multiple Account support
    3.  IMAP Support
    4.  Calendar Integration
    5.  SMTP Support
    6.  Email Organizer
    7.  Add-ons
    8.  Built-in RSS reader
    9.  POP3 Support
    10.  Graphical User Interface
    11.  Dark Mode
    12. Google Calendar icon  Google Calendar integration

    Thunderbird VS K-9 Mail

     
    Comments about Thunderbird as an Alternative to K-9 Mail
    Tubby 9417
    Positive Oct 11, 2023
    0

    A really great client used by many, popular because it supports almost every mail provider (not proton ?), and mail providers provide documentation to integrate with Thunderbird. I recommand

    K-9 Mail Icon
    Thunderbird icon
    • Most users think Thunderbird is a great K-9 Mail alternative.

    • Thunderbird is the most popular Windows, Android, Mac & Linux alternative to K-9 Mail.

    • Thunderbird is the most popular Open Source & free alternative to K-9 Mail.

    • Thunderbird is Free and Open SourceK-9 Mail is also Free and Open Source
    • Thunderbird is CustomizableK-9 Mail is not according to our users
  2. FairEmail icon
     79 likes
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    Open-source, privacy-focused email client offering features such as encryption via OpenPGP and S/MIME, unlimited accounts, a unified inbox, customizable settings, and reformatted emails to prevent phishing. Supports two-way synchronization and provides Pro features for additional customization.

    43 FairEmail alternatives

    License model

    • FreemiumOpen Source

    Application type

    Country of Origin

    • NL flagNetherlands
    • European Union flagEU

    Platforms

    • Android
    • Android Tablet
    • F-Droid

    Properties

    1.  Privacy focused
    2.  Customizable
    3.  Lightweight

    Features

    1.  Multiple Account support
    2.  Email Notifications
    3.  PGP Encryption
    4.  Extensive settings menu
    5.  IMAP Support
    6.  Notifications
    7.  No Tracking
    8.  Works Offline
    9.  Ad-free
    10.  Unified inbox
    11.  Dark Mode
    12.  S/MIME Support

    FairEmail VS K-9 Mail

     
    Comments about FairEmail as an Alternative to K-9 Mail
    LongLife
    Positive Feb 8, 2024
    0

    Both are opensource, privacy oriented, free email clients for Android

    K-9 Mail Icon
    FairEmail icon
    • Almost everyone thinks FairEmail is a great K-9 Mail alternative.

    • FairEmail is the most popular Android Tablet alternative to K-9 Mail.

    • FairEmail is Freemium and Open SourceK-9 Mail is Free and Open Source
    • FairEmail is Privacy focused and CustomizableK-9 Mail is not according to our users
  3. Copy a direct link to this comment to your clipboard

    Streamline emails, calendars, contacts, and task management with a smart inbox prioritizing critical messages. Includes calendar scheduling, third-party app integration like Facebook, Dropbox, and Trello, and support for Microsoft Exchange, Outlook.com, and Gmail, ensuring efficient task and email handling.

    126 Microsoft Outlook alternatives

    License model

    Application types

    Country of Origin

    • US flagUnited States

    Platforms

    • Mac
    • Windows
    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Apple Watch
    • Android Wear

    Top Microsoft Outlook Features

    1.  Exchange
    2.  Native application
    3.  Email Organizer
    4.  Calendar Integration
    5.  Calendar View
    6.  Cloud Sync
    7.  Support for @mentions
    8.  Unified inbox
    9.  Multiple Account support
    10.  Works Offline
    11.  Support for Aliases
    12.  Dark Mode

    Microsoft Outlook VS K-9 Mail

     
    Comments about Microsoft Outlook as an Alternative to K-9 Mail
    Guest
    Negative May 14, 2019
    5

    Microsoft Office Outlook has more vulnerabilities and so far, seems more of a memory hogger on my device than K-9 Mail. Thank you, K-9 Mail!

    Guest
    Negative Oct 5, 2024
    0

    If you use outlook for another email it will strore the password on a Microsoft server

    K-9 Mail Icon
    Microsoft Outlook icon
    • This alternative is disputed. Microsoft Outlook is a legitimate K-9 Mail alternative, but it might have issues that some users think are important.

    • Microsoft Outlook is the most popular Web-based, iPhone & iPad alternative to K-9 Mail.

    • Microsoft Outlook is the most popular commercial alternative to K-9 Mail.

    • Microsoft Outlook is Paid and ProprietaryK-9 Mail is Free and Open Source
  4. Spark Mail icon
     131 likes
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    E-mail app with all the great features: swipes (long/short), snooze, add (multiple) attachments from the cloud, support for various e-mail services and more.

    61 Spark Mail alternatives

    License model

    • FreemiumProprietary

    Application types

    Country of Origin

    • UA flagUkraine

    Platforms

    • Mac
    • Windows
    • Android
    • iPhone
    • iPad
    • Apple Watch

    Top Spark Mail Features

    1.  Multiple Account support
    2.  Email Scheduling
    3.  Snooze Mail
    4.  Cloud Sync
    5.  Calendar Integration
    6.  Dark Mode
    7.  Email Organizer
    8.  Unified inbox
    9.  Works Offline
    10.  Mail Filtering
    11.  Ad-free
    12. Google Calendar icon  Sync with Google Calendar

    Spark Mail VS K-9 Mail

     
    Comments about Spark Mail as an Alternative to K-9 Mail
    abogawat
    Positive Oct 31, 2023
    0

    Spark is one of the most polished email clients out there, with multi-platform support and an excellent feature set. The free version is good enough for most people.

    K-9 Mail Icon
    Spark Mail icon
    • Almost everyone thinks Spark Mail is a great K-9 Mail alternative.

    • Spark Mail is Freemium and ProprietaryK-9 Mail is Free and Open Source
  5. Canary Mail icon
     26 likes
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    Canary can write your emails, prioritize what needs attention, silence spam & much more. Say hello to your Inbox Copilot!

    License model

    • FreemiumProprietary

    Application types

    Country of Origin

    • GB flagUnited Kingdom

    Platforms

    • Mac
    • Windows
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Apple Watch

    Properties

    1.  Privacy focused
    2.  Lightweight

    Features

    1.  End-to-End Encryption
    2.  Unified inbox
    3.  PGP Encryption
    4.  Multiple Account support
    5.  AI-Powered
    6.  GPG Encryption
    7.  Dark Mode
    8.  No Tracking
    9.  Cloud Sync
    10.  Ad-free
    11.  Reminders
    12.  Encrypted Email

    Canary Mail VS K-9 Mail

     
  6. Copy a direct link to this comment to your clipboard

    Infomaniak’s Mail Service is a secure emailing system hosted in Switzerland and is the best (free) alternative to the web giants. Infomaniak’s emailing service is used by more than a million companies and individuals throughout Europe.

    41 Infomaniak kMail alternatives

    License model

    • FreemiumOpen Source

    Country of Origin

    • CH flagSwitzerland

    Platforms

    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • F-Droid

    Properties

    1.  Privacy focused

    Features

    1.  Ad-free
    2.  No Tracking
    3.  Portable
    4.  Calendar Integration
    5.  Multiple Account support
    6.  Cloud Sync
    7.  Support for Aliases
    8.  Real time collaboration
    9.  Secure mail
    10.  Sync Contacts
    11.  Calendar Sync
    12.  CardDAV Support

    Infomaniak kMail VS K-9 Mail

     
    Comments about Infomaniak kMail as an Alternative to K-9 Mail
    Guest
    Negative Jul 21, 2024
    0

    The Infomaniak client only works with Infomaniak mail accounts, while K-9 Mail supports all mail accounts that use the standard IMAP and SMTP protocols

    K-9 Mail Icon
    Infomaniak kMail icon
    • Infomaniak kMail is Freemium and Open SourceK-9 Mail is Free and Open Source
    • Infomaniak kMail is Privacy focusedK-9 Mail is not according to our users
  7. BlueMail icon
     33 likes
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    BlueMail is a modern, mobile first, powerful Email management tool with a sleek design, unified inbox and support for all your accounts: IMAP,Exchange,POP3.

    31 BlueMail alternatives

    License model

    • Free PersonalProprietary

    Application type

    Country of Origin

    • US flagUnited States

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • iPhone
    • Chrome OS
    • Android Tablet
    • iPad
    • Apple Watch

    Properties

    1.  Lightweight

    Features

    1.  Unified inbox
    2.  IMAP Support
    3.  Ad-free
    4.  GDPR Compliant
    5.  Multiple Account support
    6.  Calendar Integration
    7.  POP3 Support

    BlueMail VS K-9 Mail

     
  8. Shortwave icon
     15 likes
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    Shortwave is an email app that takes the pain out of managing your inbox, making it effortless to stay organized, productive, and responsive.

    18 Shortwave alternatives

    License model

    • FreemiumProprietary

    Application type

    Country of Origin

    • US flagUnited States

    Platforms

    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Gmail

    Properties

    1.  Lightweight

    Features

    1.  Dark Mode
    2.  Email Organizer
    3.  AI-Powered
    4.  Email Scheduling
    5.  Ad-free
    6.  Push Notifications
    7.  Multiple Account support
    8.  Calendar Integration
    9.  Support for Aliases
    10.  No Tracking
    11.  Spam Filter
    12.  Mail Filtering

    Shortwave VS K-9 Mail

     
  9. Librem Mail icon
     3 likes
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    End-to-end encrypted email used by nearly everybody already.

    License model

    Application type

    Country of Origin

    • US flagUnited States

    Platforms

    • Android
    • Android Tablet

    Librem Mail Features

    1.  End-to-End Encryption
    2.  IMAP Support
    3.  POP3 Support

    Librem Mail VS K-9 Mail

     
  10. Ltt.rs icon
     2 likes
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    No-frills, easy to use, easy to maintain Email client for Android based on the JSON Meta Application Protocol (JMAP).

    License model

    • FreeOpen Source

    Application type

    Country of Origin

    • DE flagGermany
    • European Union flagEU

    Platforms

    • Android
    • F-Droid

    Properties

    1.  Lightweight
    2.  Minimalistic

    Features

    1.  Works Offline
    2.  JMAP

    Ltt.rs VS K-9 Mail

     
  11. Aqua Mail icon
     12 likes
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    AquaMail is an email app for Internet and Exchange mail, for Android 4.0.3 and higher.

    License model

    • FreemiumProprietary

    Application type

    Country of Origin

    • BG flagBulgaria
    • European Union flagEU

    Platforms

    • Android
    • Android Tablet

    Properties

    1.  Lightweight
    2.  Customizable

    Features

    1.  Dark Mode
    2.  Multiple Account support
    3.  Unified inbox
    4.  Support for Aliases
    5.  Works Offline
    6.  IMAP Support

    Aqua Mail VS K-9 Mail

     
  12. TypeApp icon
     30 likes
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    TypeApp is an all-free, beautifully designed, universal email app, capable of managing unlimited number of mail accounts from various providers, allowing for smart push notifications while enabling personalization across multiple email accounts.

    License model

    • Free PersonalProprietary

    Application type

    Country of Origin

    • US flagUnited States

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Android Wear
    • Kindle Fire

    Properties

    1.  Privacy focused

    Features

    1.  Unified inbox
    2.  Email Organizer
    3.  Multiple Account support
    4.  Live Push Notifications
    5.  Exchange

    TypeApp VS K-9 Mail

     
12 of 21 K-9 Mail alternatives