I arrived very late, around 04 a.m., and had no problem checking in (I didn't reach them on the phone or mail beforehand, though). But there was absolutely no problem checking in at that time. I was upgraded to a family room since the hotel was fully booked. Small window with no interesting view, but the room was otherwise great - clean and modern, with a plethora of mains outlets in the right spots, and even some USB outlets for charging. Oh, and the hotel is quiet, despite its location in the middle of Soi 11. Highly recommended.