I've never seen a mobile phone that is the least bit resistant to moisture.
Dynamic microphones made using polymer diaphrams and support structures would be completely impervious to moisture (even Immersion), specially true if the electronics cannot short through the water.
Electret condensers I would think would be hard to make completely moisture proof. A double diaphram type design would work, the design would be tricky though, the passband could be quite bad unless serious consideration was made. Also the electronics in this case would be more complex and harder to seal. (Though epoxy dip should work.)
True condensers would be even harder. Most run on a phantom power supply, and the electronics are even more complex. Also condenser mics are generally the ones with the flattest response, these mics can get to rediculous prices.