Seashore is not available for Windows but there are plenty of alternatives that runs on Windows with similar functionality. The best Windows alternative is GIMP, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 100 alternatives to Seashore and loads of them are available for Windows so hopefully you can find a suitable replacement. Other interesting Windows alternatives to Seashore are Krita (Free, Open Source), Adobe Photoshop (Paid), Paint.NET (Free Personal) and Affinity Photo (Paid).
Krita is a professional Free and open source (FOSS) painting program. It is made by artists that want to see affordable art tools for everyone withith concept art, texture and matte painters, illustrations and comics.
MyPaint is a fast painting program with an emphasis on full-screen use. It lets you focus on the art instead of the program. You work on your canvas with minimum distractions, bringing up the interface only when you need it.
MediBang Paint is a lightweight software for illustration and making comic books on Windows and Mac OS. Features -You can save multiple pages in one file. -Perspective grids for easily drawing backgrounds or speed lines.
PaintTool SAI is high quality and lightweight painting software, fully digitizer support, amazing anti-aliased paintings, provide easy and stable operation, this software make digital art more enjoyable and comfortable. Details: - Fully digitizer support with pressure.