- Peninei Halakha
One may not wear high-quality shoes on Tisha Be-Av. In the past, high-quality shoes were commonly made from leather, since people did not know how to make strong, flexible, and durable shoes from other materials. There is a dispute among the poskim about the status of non-leather shoes. Some Rishonim were stringent and ruled that one may not wear such shoes on Tisha Be-Av if they actually protect the foot from the ground (Rashi, Rambam, Tosafot, Rabbeinu Yeruĥam). Other Rishonim permitted wearing such shoes on Tisha Be-Av even if they protect one’s feet from the rough ground (Ramban, Rosh, Rashba). Most of the Aĥaronim ruled in accordance with the latter Rishonim in practice (sa 614:2).
Despite this, it seems clear that the lenient position was based on the reality of the time, in which all non-leather shoes were uncomfortable for walking, and thus it could be claimed that these were not considered proper shoes. Today, however, when manufacturers commonly produce high-quality non-leather shoes, one may not wear shoes of any material on Tisha Be-Av if it is a kind of shoe that people would wear year-round to walk on rocky ground. In the previous generation, when it was still uncommon to find high-quality shoes made from different materials, some poskim permitted wearing such shoes on Tisha Be-Av. However, as time goes by and excellent shoes made from different materials become increasingly common, fewer and fewer poskim permit wearing such shoes on Yom Kippur.
Therefore, any shoe that people can wear outdoors on rocky ground may not be worn on Tisha Be-Av, no matter what the material of the shoe is. Thus, footwear such as “Crocs,” “Keds,” and “Converse All-stars” may not be worn on Tisha Be-Av. However, one may wear cloth slippers or very thin rubber shoes, since people generally would not wear these shoes when walking on rocky ground as one can feel the roughness of the ground when wearing them. Nonetheless, since there are still poskim who are lenient regarding non-leather shoes, one should not rebuke those who wish to rely on this opinion. (See Ohalah shel Torah 2:81; Hilkhot Ĥag Be-ĥag 22:25 [in the name of R. Yosef Shalom Elyashiv]; this topic is explained in detail in Peninei Halakha: Days of Awe 8:5).
Sick people and postpartum women, who are liable to catch a cold if they walk barefoot on the ground, may wear leather shoes. Similarly, one who is walking in an area where there is concern for scorpions and the like may wear leather shoes. Likewise, one who is walking in a muddy place may wear his regular shoes in order to avoid soiling his feet. A soldier on active duty may wear army boots (sa 554:17, 614:3-4). The reason for all these leniencies is that wearing shoes is prohibited on Tisha Be-Av only if one wears them for the sake of comfortable walking. When there is different reason for wearing them, however, the prohibition does not apply.
If one requires orthotic shoe inserts and suffers without them, one may insert them into a slipper or thin rubber shoe that people generally would not wear throughout the year. This is permitted because one is not using these inserts for the sake of comfortable walking but in order to relieve his suffering. In addition, since the insert is not attached to the shoe, it can be claimed that it is not part of the shoe (Ĥelkat Yaakov 2:83; Shemirat Shabbat Ke-hilkhatah 39:37).