Ryan Lochte just unloaded his giant Gainesville, Florida swimming pool ... which also happened to have a house attached to it, TMZ has learned.

The Olympic gold-medalist bought the pool way back in 2006 for $377,500 while he was still attending the University of Florida ... and sold it in late August for an undisclosed amount.

The pool comes with a 2,470 square-foot house (below) that boasts 4 bedrooms ... 2 baths and other home-esque things ... like a garage ... exterior walls ... fireplace etc.

But from the pics, it's obvious ... Lochte bought the place for the pool, which takes up the ENTIRE back yard.

The timing of the sale (which closed just 4 days after the 2012 Games ended) came as no surprise ... considering the 11-time-Olympic medalist has repeatedly said that he wants to move to L.A. and pursue other careers ... like reality TV.