It's monkey see monkey do for Tom Brady and his daughter Vivian ... because after she jumped off the top deck of a yacht, he followed suit ... and it's all on video.
TB12 is doing the mega yacht thing off the coast of Ibiza and he just shared one of the more adventurous parts of his day with his 12-year-old.
First, Vivian jumps off the edge of the yacht's second deck and splashes down into the Mediterranean Sea.
Tom says .