GCC 16.2 can be installed directly from the Ubuntu 26.10 repositories. On Ubuntu 24.04, the exact release can instead be built from source alongside the existing GCC 13 installation. This guide puts the package-based installation first, followed by the source build, then shows how to switch GCC and G++ together with update-alternatives for existing CMake projects.

Choose the installation section for your Ubuntu release. Ubuntu 26.04 LTS and Ubuntu 26.10 have different GCC packages: the catalog checked for 26.04 lists a development snapshot, while 26.10 provides GCC 16.2. These are installation instructions; the source-build starting machine has Ubuntu 24.04 on x86-64 and GCC 13.3.0.