A tallis koton may be worn in the bathroom, either above or below one’s shirt. A tallis gadol, which is normally worn for davening, should not be worn in the bathroom. Similarly, some poskim forbid one to wear a kittel, which is also designated for tefilla, when walking into the bathroom. Others allow it to be worn, but it must be removed before tending to one’s needs. In some communities it is customary to wear a white chalat during the Yamim Noraim. This garment may be worn in the bathroom, since it is not designated for davening.
[שו"ע כא, ג, ומשנ"ב יד; ביאורים ומוספים דרשו, 8 ,10 ו־11]