How do I get the full path to an asset?

AssetDatabase.GetAssetPath returns me a path relative to the project directory.
Application.dataPath returns me the absolute path to the data directory (usually inside the project).

I can’t find the path of the project directory anywhere, though. I want to use it in conjunction with the asset path to have a full path. Anyone know how to get that?

Application.dataPath should work if you strip the "/Assets" part of it. See the reference: It returns <path to project folder>/Assets when called in the editor.

Are you sure you want the full path? The Current Work Directory is set to the project directory, so you certainly can use a relative path when passing paths to system functions, etc.