In the 2026 MLB season around trade-deadline time, Major League Baseball had 30 teams.
MLB’s 30 clubs are divided evenly between the American League and National League, with 15 teams in each league. Each league is organized into three divisions—East, Central, and West—with five teams per division.
The league’s membership had remained at 30 since the 1998 expansion season, when the Arizona Diamondbacks and Tampa Bay Devil Rays joined. The Athletics’ move to Las Vegas Ballpark for selected 2026 home series did not create a new franchise; it was a venue arrangement involving an existing club.
Trade-deadline coverage often focuses on buyers, sellers, and playoff contenders, but the deadline does not change the league’s membership. A trade moves players between clubs, while expansion would be required to raise the number of MLB teams.