A dedicated passport wallet always seems a little fancy. They usually have too many slots and are big and floppy.
We love this compact little one from Billykirk, another company who consistently makes beautiful, useful and well-made products right nearby in Jersey City.
This wallet could slip into a front or rear pocket if you are dashing around foreign lands in shorts and a T-shirt. It is also elegant enough to slip inside pocket of a blazer (preferably a Peter Manning blazer) if you are traveling in higher style.