What to wear under getting ready robe?

I bought everyone white capri leggings. The robes aren't super short, but it might make everyone more comfortable.

I'm also trying to figure this out. I think we'll probably just wear shorts and tanks too.

I wore a robe when I was a bridesmaid in a friends wedding. I think we did end up wearing bras (so that isn't super helpful), but we did all safety pin the tops to hold it together so nothing slipped out haha and I think we all just wore athletic shorts underneath. I think we would have been more prepared but we all packed to spend the night with the bride & she gave us the robes at rehearsal dinner so we weren't expecting them.

I've heard a button-up is best so you can take it off without disturbing your hair or makeup

I would guess that most of my ladies will be doing the pajama thing. Since all of their dresses have straps of some kind, the bra lines are of no concern. Me, however, it's not the shoulder bra lines I'd worry about (my dress does have straps with a lace applique on the shoulder) it's the back lines! So I will probably just be wearing some leggings or pajama pants and a loose, "easy to remove over my head without disturbing the hair" tank top with the build in bra shelf (which doesn't support much, but makes me feel better) unless I can find a bandeau bra fairly quickly to wear under a button down of some sort.

My sister wore leggings but the rest of us just wore strapless bras and underwear.

I wore an strapless bra (the same one I was wearing under my dress and leggings I already owned. when it came time to change for pictures I took my leggings off and put on nude spanx so you couldn't see through it and it looked like I was just wearing the robe. The robe my FH bought me as a wedding gift to wear was super see though so I definitely recommend wearing something underneath. Also remember don't wear anything that has to go over your head as it may damage your hair or make up.

Leggings are a great option... maybe all wear the same color leggings so you can have cute pics.