OpenFOAM is available from the OpenFOAM Foundation which licenses it free and open source under the General Public Licence.  The OpenFOAM downloads are produced and maintained by us — CFD Direct — on behalf of the Foundation, in two forms for Ubuntu, Other Linux, macOS and Windows:

Ubuntu Linux

Packaged version of OpenFOAM for Ubuntu Linux, with a simple installation.

Other Linux OS

Installation on other Linux OS by compiling the OpenFOAM source code.

macOS

Installation of the OpenFOAM package for Ubuntu using Canonical Multipass.

Windows

Installation of the OpenFOAM package for Ubuntu using Windows Subsystem for Linux

Download Archive

Older versions of OpenFOAM can be found in the download archive, with release notes in the release history

CFD Direct From the Cloud

Alternatively avoid downloading and installing OpenFOAM by running CFD Direct From the Cloud