Cardi B is playing Santa Claus this year -- only she's doing it without the big red hat, reindeer or sleigh -- and will bring smiles to a ton of kid's faces.

Cardi was spotted in Miami Friday spending a bunch of money on gifts for kids at a local Target store. The rapper also had a U-HAUL rented to load the presents and ship em off for those in need.

We're told in total, Cardi spent about $5,000 on everything from games, dolls, car sets and more. She had staffers help her load everything up in the truck.

It's unclear exactly where the gifts will go -- Cardi talked about helping kids out in New York -- but nonetheless, it's an awesome gesture.

Cardi's daughter, Kulture, will be celebrating her second Christmas this year, and if mom's spending for other kids on Friday is any indication ... it's about to be a big year.