Koh ji mal~
But those are Tae's child bearing hips

There's no way it's not her...
then again, it looks like there's a belly piercing under there which the "real" Tae doesn't have.
And by the way,
SITS, nothing wrong with the way Koreans go to the beach. From personal experience, it's a lot more convenient and comfortable to wear something like what her friends are wearing. Sometimes looking cute is hotter ;]
You should know that, Mr. Tae lover!
-O_sLaVe