I have two pairs of Newport H2's, one with the rubbery sole and one with a leather sole. With the regular rubbery sole, I never had a problem with them getting slippery or anything when they are wet. And I've worn them many times to go kayaking or swimming in lakes, where they've been completely submerged. They dry out pretty quickly, and really are great all around shoes (I wear them hiking as well). I have worn them with socks at DW, just to give my feet some more cushion, but that obviously makes them feel warmer. Without socks, they've never given me problems.
The ones with the leather soles, on the other hand, did feel slippery after getting wet (I've never worn those completely in the water). But they still dried pretty quickly. With those, I found it more comfortable to wear socks, as they didn't seem to breathe as well as the rubber sole for some reason. The great thing about Newports is that you can wear a really low cut sock and they are pretty much completely hidden around your ankle.