Kobe Bryant Announces Retirement ... I'm Ready to Let Go

This will be Kobe Bryant's final season in the NBA ... he just made it official by penning a love letter to basketball.

Kobe says the 2015-16 season will be his last in the Lakers purple and gold -- and any other uniform. In the letter, posted on The Players' Tribune, Kobe writes ... "Dear Basketball, From the moment I started rolling my dad's tube sock and shooting imaginary game-winning shots ... I fell in love with you."

He also said, "This season is all I have left to give. My heart can take the pounding, my mind can handle the grind, but my body knows it's time to say goodbye. And that's OK. I'm ready to let you go."

The letter's pretty extraordinary, and kind of emotional.

37-year-old Kobe closed with -- "I'll always be that kid with the rolled up socks. Garbage can in the corner, :05 on the clock, ball in my hands. 5 ... 4 ... 3 ... 2 ... 1. Love you always, Kobe."