Daily Halacha: Costumes and Prayer: What’s Permitted According to Halacha?

Is it allowed to dress a child in a four-cornered costume without tzitzit, such as a Kohen Gadol, who served in the Beit HaMikdash (Holy Temple)?

According to the Shulchan Aruch, once a child is old enough to understand how to wrap himself in a tallit (prayer shawl), the father should buy him a small one with tzitzit (the fringes tied to four-cornered garments, as commanded in the Torah).

However, in the case of a costume when the child is only dressing up for fun and is not actually using the garment as regular clothing, then it is allowed, even if the garment has four corners and no tzitzit.

Still, to fulfill all opinions, it's a good idea to simply round off one of the corners of the costume so that it no longer has four distinct corners.

Is it allowed to pray while wearing a costume?

It’s more respectful to remove the costume before praying, especially if the costume is of an animal or something not appropriate for prayer. While it's not a strict prohibition, halachically it is better to daven (pray) in regular clothing that reflects the seriousness of standing before Hashem.
(Based on Yalkut Yosef)

Ach Tov VaChesed – Daily Halacha