May a person bring a tape or disk player into the shower, so he can listen to Torah classes while bathing?
With regard to Torah study while unclothed, Halacha distinguishes between verbal and silent learning. Although it is forbidden to speak words of Torah when one is undressed, one may think words of Torah in his mind under such conditions. By the same token, it is permissible to hear words of Torah – without speaking them – when one is not wearing clothes. In principle, then, it is permissible to hear words of Torah – either live or recorded – in the bath or shower.
It should be noted, however, that it is forbidden to even think Torah matters silently in a restroom. Restrooms contain a kind of spiritual contamination, and one may therefore not even think or hear words of Torah in the restroom. Hence, if one’s shower is situated in the restroom, in the same room as a toilet, it is forbidden to think or hear words of Torah in the shower.
This is the ruling of Hacham Ovadia Yosef, in Halichot Olam and in Yabia Omer (vol. 5). Hacham Ovadia adds that this ruling applies only in private showers, such as the shower in one’s home. Public bathhouses have a different status, and one may not think or listen to words of Torah in a public bathhouse or shower.
Summary: It is permissible to listen to a Torah class while bathing or in the shower, provided that the shower or bath is not in the restroom, and that it is not a public shower.