The mascara: Dior Black Out Waterproof

This mascara stays on really well -- no flaking, running or general undereye smeariness. My only complaint is the wand. Because the bristles are long and thick, I found it almost impossible to avoid getting mascara on my lids during application, which means I'm wetting a Q-tip and attempting to wipe it off without causing my lashes to clump together -- a near-impossible feat. I also found that volume and curliness I first experienced was sacrificed after a couple hours hiking. Though the formula is OK -- I have faith it could withstand a sad-movie-induced ugly cry without producing raccoon eyes -- I can't use it because the application is too messy and the volume doesn't last, at least during sweaty activities. --Emily Woodruff

The mascara: Maybelline Great Lash Waterproof Mascara

After my hot yoga session, I was so Zen and relaxed, and felt superlimber afterward. But even better: my lashes still looked fantastic. I didn't even make efforts during the class to wipe my face as sweat was trickling everywhere. I just let it happen. And when I looked in the mirror, my eyes still looked good. No smudging or running anywhere. I should also note that I had the mascara on during the day, went to the class at 5:15 p.m. and then stepped in a steamy shower afterward and still, the mascara was intact. In fact, I had to use an oil-based cleanser and Vaseline to get all of it off that night (a small price to pay for all-day lashes). --Paulina Kay

The mascara: Make Up For Ever Aqua Smoky Lash

"Waterproof" and "lengthening" seem to be mutually exclusive when it comes to mascara, but that's not the case with Make Up For Ever Aqua Smoky Lash. Not only did this waterproof version of the brand's classic Smoky Lash mascara give me fluttery, pretty lashes, it also would not budge -- no matter how much sweat got in my eyes. The formula is pigmented, but runny, so be sure to give it a couple minutes to dry before sweating all over it. --Allie Flinn

The mascara: E.L.F. Lengthening and Volumizing Waterproof Mascara

This cruelty-free, drugstore mascara held up surprisingly well during the grueling conditioning portion of my Sunday morning workout (think: lots of running and rowing). When you factor in the sunny weather and my predisposition toward sweatiness, you'll realize this is no easy feat. Since I don't typically wear waterproof mascara other than when working out, I like that this one got the job done without costing a ton of money, and looked pretty natural while still giving my lashes the definition they need. --Allie Flinn

The mascara: Clinique High Impact Waterproof Mascara

I love the wand on this mascara. It's small, neat and applies mascara very precisely. But how does its waterproofing ability measure up? During my run, I pushed myself a little more than usual in order to get the beads of sweat rolling down my face. (If you ever need to get in shape fast, volunteer to sweat-test several mascaras.) Once I felt the salty sting of sweat entering my eyeball, I knew the test was complete. When I got home, I looked like a mess -- except for my mascara, which was still perfectly in place. Overall, this waterproof mascara is great for a natural look, and it holds up well, but if you want a lot of drama (I don't, especially when I'm running), you may want to look for one with more volume-producing capabilities. --Emily Woodruff