The world-class ski legend is on a secret trip for a secret project with her adorable pup Lucy Vonn ... and it doesn't take a whole lotta investigative reporting to know it's a bikini thing.

Vonn recently hooked up with L Space -- a bikini company -- and by the looks of things, they made a good choice in a spokesperson!

The 35-year-old Olympic superstar has had a pretty massive year -- she got engaged to her NHL star boyfriend P.K. Subban (remember they proposed to each other?!) and officially retired from competitive downhill skiing.

The good news ... she's got options!