Given the prohibition of wearing certain footwear on Yom Kippur, is one allowed to wear Crocs on Yom Kippur? Or are they too comfortable or something?
Strictly according to the law, there is no problem with Crocs. I've seen many תלמידי חכמים who wear Crocs on Yom Kippur. However, there is an opinion that Crocs are too comfortable.
Basically there are two opinions about yom kippur shoes. One is that anything non-leather is fine. The other is that they should also be not-too-cushiony. While the former seems to be common practice, the latter is cited as a good practice by many poskim.
So there are three possibilities about crocs:
- They are permissible (former view)
- They are prohibited (latter view)
- They are less-than-ideal (somewhere in between)
Rabbi Brody concluded that in his opinion, to say 3 was not an absurd chumra.
Rabbi Elyashiv ZY"A said that the wearing of Crocs on Yom Kippur is "permissible legalistically, but it is inadvisable," because they are too comfortable. (Source)
At the Shabbos Shuvah Drasha 5775, my rav mentioned that while they might be "legally correct", they are not in the spirit of the day because they are "too casual". Canvas sneakers are better. He did not go into detail beyond this. He also said that if that is all you have, then that is what you would have to wear.