It's the season of giving ... which means boxing superstar Errol Spence got himself an AMAZING Cartier watch for the holidays ... and it's got a $100k price tag!!
TMZ Sports has learned, the champ wanted to treat himself at the end of the year ... so he hit up his go-to guy, Iceman Nick, to make him a one-of-a-kind diamond Cartier watch!!
We're told it's a one-of-one 2-tone Santos de Cartier Skeleton watch ... which is decked out with 30 carats of VVS diamonds, 18k rose gold screws and bezel, 7-sided crown set with a faceted sapphire, blue-steel sword-shaped hands and a sapphire crystal case back.