According to ratings released Tuesday by Viacom and CBS, which broadcast the game, the game had 96.4 million viewers.
That's the smallest audience share for any Super Bowl since 2007.
The Buccaneers routed the Chiefs 31-9 in Super Bowl LV, which gave Tampa Bay quarterback Tom Brady his record seventh championship.
Television viewers numbered 91.7 million, but CBS said streaming viewers (5.7 million) brought the "highest average minute audience for any NFL game" and were up 65% over last year's game.
CBS said the markets with the highest viewership were Kansas City, Tampa, Fla., and Boston, where Brady played last year and the bulk of his career.