You can absolutely wear Crocs in Japan, but there is some specific etiquette to keep in mind. Japan is a culture that prioritizes footwear that is easy to remove, as you’ll be taking your shoes off constantly at temples, traditional restaurants, and even some changing rooms. In this regard, Crocs are actually quite practical because they slip on and off easily. However, "street" Crocs are never to be worn inside someone’s home or on tatami mats. Additionally, be aware that in very crowded cities like Tokyo, people tend to dress more formally or "neatly" than in the US; while you won't be kicked out of anywhere for wearing Crocs, you might feel a bit underdressed in high-end shopping districts like Ginza. Lastly, always wear socks if you plan on visiting temples, as walking barefoot on the wood floors is often considered disrespectful.