At least she's got her water wings (Ba-Bum TISH!).



On the subject of how winged ponies swim underwater I do think it's possible for them (I think there was at least one episode were we saw Rainbow Dash swimming), maybe the trick is keeping their wings folded up (Either that or using them along with their legs to help them swim).



And... Well, someone's gonna say it eventually so it might as well be me, SHOO BE DO, SHOO SHOO BE DO!