What type of bra?

A regular strapless bra should work for both of them, depending on the backs.

I had cups sewn into my dress so I didn't wear a bra, only pasties. I had dress tape on too. My dress also had boning so it helped with staying tight on my body.

My dress is strapless, and when I bought it at David's Bridal, they recommended the "bralette" that I used to try dresses on. It's basically a strapless bra that comes down over your ribcage, like a bustier. I love it!!

I had cups sewn into my strapless dress so that I don't have to wear a bra!

I had cups sewn into my dress, but that was only because it helped me look perkier. Look into strapless or those deep V or U cut body suits made for wedding gowns, I think its wedding shapers??

Look for a strapless bra if you really want to wear a bra (VS has great ones), but personally, I'd go without a bra and just add cups or wear petals.

Strapless (depending on the back). But if the dress is structured enough I would consider just having cups added and going braless, especially for that strapless one. With enough boning, a stiffer fabric, and the right fit a dress can hold you in really well without the addition of a bra. The second dress looks like it has a mesh panel in front, so that might not be a strong or supportive enough fabric to go braless with.

Whenever I have a dress I can go braless in I am just more comfortable than when adding a strapless bra and the extra cost for cups and fitting is worth not feeling itchy or like I'm being squeezed all night. I'm planning to go braless in my dress, but will use silicone pasties or boob tape to help hold me in and prevent a nip slip.

Strapless or none at all? Does the dress have cups? If so, some people can get away without a bra at all...

I plan on getting my tailor to add straps and reinforce the bust so that I don't have to spend the night in an uncomfortable bra pulling up my dress! I want to eat, drink, and DANCE to celebrate my marriage, not spend the night hoping no one sees things they shouldn't!