Trending Size 38 In Us Shoes Birkenstock / Birkenstocks are a german brand of sandals, notable for their contoured cork and rubber footbeds (soles), which conform somewhat to the shape of their wearers' feet. you want your foot all the way to the back of the shoes, and i have birkenstocks in both size 37 & 38 and they all for comfortably. Conversion table including eur shoe sizes, au shoe sizes and cm to exactly measure your feet and match them with the correct size. Size 38 In Us Shoes Birkenstock - Birkenstock brown leather slingback sandals size 38 eu or 7 to 7.5 us.