German soccer superstar Jerome Boateng is on a mission to be the most iced out player in the game ... going on a $350k watch and chain jewelry spree!!!
TMZ Sports has learned ... the 30-year-old Bayern Munich defender wanted to treat himself with some shiny new gifts ... hitting up Gabriel the Jeweler for the job.
We're told Boateng copped an Audemars Piguet watch with a custom VVS diamond bezel decked out with 30 carat stones ... and a 1 kilo Cuban link choker with 120 carat VVS diamonds.
FYI -- Gabriel is the go-to guy for guys who play the other football as well -- like Antonio Brown, Odell Beckham and Amari Cooper.