Carlos Rivera was a human male who served as an ambassador of the United Federation of Planets and senior member of the Federation Diplomatic Corps during the 2270s.

In 2270, Rivera was assigned to negotiate with denizens of the Lorealyn system to join the Federation. While en route aboard the USS Magnan, Rivera and the ship's crew were captured by Klingons and released shortly thereafter. (FASA RPG module: Star Trek IV Sourcebook Update).