Eclipse - How to know on which workspace I'm working without clicking/changing main view

If the full path (as shown in the other answer) is to long, then you can use Window -> Preferences -> General -> Workspace -> Workspace Name instead to set a self defined label for each workspace, which is then shown prominently in the title bar.

try to add the option

-showlocation

in you eclipse.ini or in the command line when you launch Eclipse.

The workspace location will appear in the window title bar.

Go to Eclipse, Window -> Preferences -> General -> Workspace -> Select the checkbox for "Show workspace path in window title"