The latest Galaxy phone from the never ending lineup is the Galaxy S4 active. It’s waterpoof and dust-proof which is very practical for just about every person.
It’s pretty much the same phone as the GS4 in every way except it’s a bout 15% thicker, has a lower MP camera and it has a aqua mode for taking underwater photos. I’d still be a little weary of taking my GS4 underwater to take some pictures…you never know if the headphone jack port is 100% secure
You can see the best galaxy s4 spare battery here.