The SeaMonkey project is a community effort to develop the SeaMonkey all-in-one internet application suite. Such a software suite was previously made popular by Netscape and Mozilla, and the SeaMonkey project continues to develop and deliver high-quality updates as well as new features and improvements to this concept. Containing an Internet browser, email & newsgroup client, HTML editor, IRC chat and web development tools, SeaMonkey is sure to appeal to advanced users, web developers and corporate users.
SeaMonkey is built on the open source Mozilla Gecko engine, the same code which underlies the highly successful Thunderbird and is the base for the Firefox browser. SeaMonkey benefits from the cross-fertilization with these other projects, by gaining (and contributing) new features and the ongoing security updates which are a modern necessity. The SeaMonkey Association provides legal backing for the SeaMonkey Project.
Publisher’s description
What is SeaMonkey?
SeaMonkey by SeaMonkey e.V. (developed by SeaMonkey Council) is open-source Windows software in the web browsers category. It ranks 17th by popularity among web browsers in this catalogue. The first release dates back to 2006. It is written in C++, JavaScript, and XML User Interface Language. Besides Windows, it is available for GNU/Linux, macOS, BSD and cross-platform. Its interface is available in 17 languages.
Installation and requirements
The publisher provides EXE (NSIS) installers for 64-bit Windows. The main installer is 48.9 MB. Installation asks for administrator rights. A silent install is possible with the installer’s documented switches.
Updates and version history
The current version is 2.53.24, released on July 28, 2026. The version history goes back to August 31, 2021: 16 releases, all linked to the official files. That is about 3.3 releases a year.
Popularity and file types
The Chocolatey package has been downloaded 29,361 times. Wikipedia has an article about it in 29 of our languages. On Windows it registers 9 file types, including .html, .xhtml, .webp, .htm and .shtml. Similar programs include Brave, Waterfox and qutebrowser.
Pros / Cons
Pros
- Open source: the code can be inspected and built by anyone
- Documented silent install
- Also runs on GNU/Linux, macOS and BSD
- Mature project (since 2006)
- Interface in 17 languages
Cons
- No native ARM64 build
- Installation needs administrator rights
In short: SeaMonkey is an open-source web browser tool for 64-bit PCs. Administrators can deploy it unattended.
Screenshots
Is SeaMonkey safe to download?
- The file is served by s3.osuosl.org; check that it is the publisher’s official mirror
- The download link uses HTTPS
- A SHA256 hash is published, so you can verify the file:
1BBA47750DDF8EAAAED1C37073EA463973E5108D8A4469F6C152A598279FE12B· Open the VirusTotal report for this hash - The link answered when we last checked it (October 22, 2026)
- The source code is public
- ExeAtlas does not host, wrap or modify installers
Related guide: How to check a file’s SHA256 hash on Windows
Recent versions
All 16 versions ›16 versions over 5 years · about 3.3 a year
| Version | Date | Size | Files |
|---|---|---|---|
| 2.53.24Latest | July 28, 2026 | 50.2 MB | 64-bit EXE (NSIS)64-bit EXE (NSIS)64-bit EXE (NSIS)64-bit EXE (NSIS) |
| 2.53.23 | January 15, 2026 | 49.3 MB | 64-bit EXE (NSIS)64-bit EXE (NSIS)64-bit EXE (NSIS)64-bit EXE (NSIS) |
| 2.53.22 | September 22, 2025 | 49.3 MB | 64-bit EXE (NSIS)64-bit EXE (NSIS)64-bit EXE (NSIS)64-bit EXE (NSIS) |
| 2.53.21 | June 5, 2025 | 49.3 MB | 64-bit EXE (NSIS)64-bit EXE (NSIS)64-bit EXE (NSIS)32-bit EXE (NSIS) |
| 2.53.20 | January 27, 2025 | 49.4 MB | 32-bit EXE (NSIS)32-bit EXE (NSIS)32-bit EXE (NSIS)32-bit EXE (NSIS) |
| 2.53.19 | January 8, 2025 | 48.1 MB | 32-bit EXE (NSIS)64-bit EXE (NSIS) |
| 2.53.18.2 | January 8, 2025 | 43.5 MB | 32-bit EXE (NSIS)64-bit EXE (NSIS) |
| 2.53.18.1 | March 6, 2024 | 43.5 MB | 64-bit EXE (NSIS)32-bit EXE (NSIS) |
Install from the command line
Silent install ›winget install --id Mozilla.SeaMonkey -echoco install seamonkey -yscoop install extras/seamonkeyseamonkey-2.53.24.cs.win64.installer.exe /SRelated guide: How to use winget: install and update apps
Information
- Publisher
- SeaMonkey e.V.
- Developer
- SeaMonkey Council
- Category
- Web browsers
- Licence
- MPL-2.0
- Price
- Free
- Written in
- C++, JavaScript, and XML User Interface Language
- Interface languages
- Swedish, Spanish, Rioplatense Spanish, Slovak, Russian, and Portuguese +11 more
- Requires
- Windows 11 / 10
- Architecture
- 64-bit
- Installer
- EXE (NSIS)
- Other platforms
- GNU/Linux, macOS, BSD, cross-platform
- Version
- 2.53.24
- Released
- July 28, 2026
- First release
- 2006
- Added to the catalogue
- August 31, 2021
- Versions listed
- 16
- Updates / year
- 3.3
- Chocolatey downloads
- 29,361
- Website
- seamonkey-project.org
- winget ID
- Mozilla.SeaMonkey
- Chocolatey package
- seamonkey
- Scoop package
- extras/seamonkey
File types it opens (9)
Ratings and reviews
No reviews yet. Be the first to rate it.
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Frequently asked questions
Is SeaMonkey free?
Yes. SeaMonkey is open-source software under the MPL-2.0 licence.
Is SeaMonkey safe to download?
The download comes from s3.osuosl.org; ExeAtlas does not host or change the file. Compare its SHA256 hash with the one shown here, or open the VirusTotal report for that hash.
How do I install SeaMonkey with winget?
Open PowerShell or Windows Terminal and run the winget command shown on this page. winget downloads the official installer and checks its SHA256 hash before running it.
Can SeaMonkey be installed silently?
Yes. The silent install page lists the exact command for each installer.
Does SeaMonkey run on ARM (Windows on Arm)?
There is no ARM64 build; Windows 11 on Arm can run the 64-bit version through emulation.
Where can I download an older version of SeaMonkey?
The versions page lists all 16 versions with links to their official installer files, back to August 31, 2021.
What are alternatives to SeaMonkey?
Brave, Waterfox, qutebrowser, LibreWolf and Ablaze Floorp. The alternatives page compares them.
