How do I pay a housing deposit soon, but my ARC is with immigration for extension?

This happens more often than you would think, so banks are generally familiar with the situation. You can bring your passport and the receipt or confirmation slip from immigration showing that your ARC extension is being processed. Most banks will accept this as a temporary ID substitute. It also helps to bring a copy of your lease contract to show the purpose of the transfer.

That said, some bank branches can be stricter than others, so it is a good idea to call your branch ahead of time and ask what documents they need. If your bank gives you trouble, you can also try visiting a different branch of the same bank. Another option is to ask immigration for a temporary certificate called 외국인등록 사실증명서, which you can get from the immigration office or through the Hi Korea website even while your ARC is being processed. This document serves as proof of your registration and most banks accept it.