I can't be 100% sure about what's going on in these pictures, but it really looks like Jessica Alba is having sex in the ocean with her boyfriend.
I'm skeptical, of course, since Jessica Alba has been so annoyingly careful about keeping herself covered up, at least to the limits of decency. Catching her having sex in public would definitely be a departure from her usual style.
However, in some shots, it looks like Jessica's not even wearing her bikini bottoms (though that could just be wishful thinking). She does seem to be having a good time, though...
So, is Jessica Alba having sex in these pictures? We may never know. All I know is that's my new favourite position.