Jerry Jones just bought himself one of the sickest yachts we've ever seen -- 357 feet long with TWO helipads and a gym ... and a reported price tag of $250 MILLION!!!!

The ship is called "Bravo Eugenia" -- which the 76-year-old billionaire named after his wife, Gene Jones. It was built in the Netherlands and delivered to Jones on Dec. 20 ... an early Christmas present.

The ship can hold 14 guests with 30 members ... and has all the bells and whistles you'd expect.

Fun features include a steam room, full gym, massage room, plunge pool, rain shower and a storage area for all of the cool water toys Jones decides to take out to sea.

The interior is also top of the line -- featuring light woods and lacquered surfaces.

One of the designers, Pascale Reymond, issued a statement on his work ... saying, "We worked very closely with the Owner to find the perfect artisans and craftsmen in creating bespoke artworks, fabrics and signature furniture pieces that reflect the Owner's style and essence and combine to create a warm, inviting environment for all on board."