SEA File

What are SEA files and how to open them

Are you having problems opening a SEA file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your SEA files.

What is a SEA file?

SEA files have multiple uses, and DDA2 Self-Extracting-Archive is one of them. Read more about the other uses further down the page.

DDA2 Self-Extracting-Archive

We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

How to open SEA files

Important: Different programs may use files with the SEA file extension for different purposes, so unless you are sure which format your SEA file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested three different SEA openers which you will find listed below.

Last updated: August 13, 2026

All known file formats using extension .SEA

While DDA2 Self-Extracting-Archive is a popular type of SEA-file, we know of 2 different uses of the .SEA file extension. Different software may use files with the same extension for different types of data.

Mac StuffIt Self-Extracting Archive

Mac StuffIt Self-Extracting Archive files (extension .sea) are special Macintosh archives created by StuffIt tools (e.g. DropStuff or StuffIt Deluxe) that package compressed files together with a small executable component so that users can double-click the file and have its contents automatically extracted without needing a separate decompression program.

These archives are most commonly generated in the classic Mac OS era (versions Mac OS 8, 9 and earlier). When making a .sea archive, the creator chooses a target operating system (Mac or Windows), but a Mac-typed .sea includes Mac resource forks, Finder metadata, icon and file type information. To open one, you double-click it in the correct Mac environment and follow prompts to select where to extract the contents. Standard StuffIt archives (.sit) require a separate expansion program, whereas .sea embeds the extractor.

Technical details used to identify this format include byte signatures: for example the string "APPLaust!" at offset 65, the long signature beginning "StuffIt(c)1997-1998AladdinSystems,Inc.,http://www.aladdinsys.com/StuffIt" at offset 128, and the presence of key messages like "UNSTUFFING WAS SUCCESSFUL", "THIS ARCHIVE IS DAMAGED.", and "WWW.ALADDINSYS.COM" within the file.

SEA opener for Windows

We have identified one SEA opener that is compatible with this specific type of SEA file.

Various apps that use files with this extension

These apps are known to open certain types of SEA files. Remember, different programs may use SEA files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about SEA file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.