Are Mormon men to wear certain undergarments at different times?

Answer 1

Sure. So long as the temple garment is worn properly, anything may be worn over it. Most Church members don't want to wear regular underwear (aside from women's Bras) over the temple garment because it just adds extra bulk.

Answer 2

Adult members of the Church of Jesus Christ of Latter-day Saints (the "Mormon" church) may choose to participate in a sacred Temple ceremony called the 'Endowment'. During this ceremony, a participant is given a holy garment, which they are obligated to wear under their clothing at all times. This garment is a symbol and reminder of promises made with God during the ceremony.

So, Mormon men (and women) who have participated in the ceremony are expected to wear the holy garment (under their clothes and against their skin - like an undergarment) whenever underwear would typically be worn (even for sleeping, exercising, etc.) It is permissible to take it off while bathing or swimming. They do not wear 'certain undergarments at different times', but wear this garment at all times.

While most Mormon adults choose to participate in the ceremony at some point, those who have not participated in the ceremony may not wear the garment at any time. They wear whatever type of underclothing they choose.

Answer 3

Yes, but most devout Mormons wear underwear, or "garments" all the time.