Can I be a UX designer without being a UI designer?
The short answer is yes, but graphic design skill would make you more efficient.
UI (user interface) is simply the thing that allows human(user) to interact with machine (computer).
Graphical User Interface(GUI) is the most common type of UI these days. Whenever we interact with icons and other graphical objects, we are using this type of UI. The other types of UIs are text interface (command line), chat interface, voice interface, etc.
When designing UX, a key activity to make sure what we design works is user testing. In order to test our digital product (i.e. app), we need to prototype it. If we’re prototyping a typical app or website, then most likely they use GUI, in which case you need some graphic design skill.
You can “hack” this UI design process by using ready-made UI kits.
That said, you still need to arrange the visual elements on the screen to make them work well. That’s where the graphic design skill would come into play. Somebody who has graphic design skill would be able to do this much faster and better than UX designers who don’t have this skill.
This was originally an answer to a question on Quora: Can I be a UX designer without being a UI designer?