Joe Jonas & Sophie Turner Drop $11 Mil on Miami Mansion

Joe Jonas and Sophie Turner are moving their family down south for the winter, or so it seems, because they just scooped up a luxury home ... while still having 2 others on the market.

The still-pretty-new parents -- their daughter Willa recently turned 1 -- have bought a home in Miami for a whopping $11 million ... a waterfront property located in the exclusive island community, Bay Point.

The place is a mansion -- 10,416 square feet with 6-beds, 8.5-baths, gym, swimming pool, spa, sauna, fireplace, wine cellar, indoor gardens and a koi pond ... and plenty of space to raise a toddler.

It seems the singer and the "Game of Thrones" star got a pretty good deal too, because the place hit the market for $12 mil last year.

What's interesting about this home purchase is the timing -- Joe and Sophie just listed their 15,000 sq. ft. Encino mansion for nearly $17 mil in early summer ... but it doesn't seem it's sold yet.

Likewise, they listed their Manhattan pad about a year ago for nearly $6 mil, but there's no report of a sale there either.