Your ticket entitles you to enter the stadium as early as the gates open. The list that follows gives opening times for all thirty major league stadiums. The times shown indicate how much before game time the gates open for fans to enter. As you see, several ballparks have different opening times on weekends than on weekdays. Opening times may vary, unannounced, if there's bad weather, a doubleheader, Opening Day, or a postseason game.
Stadiums occasionally change the rules from one year to the next.
To prevent getting to the stadium too early and wasting time, or getting there too late, call the ticket office to make sure what time the gates open. In addition, not all gates at a park open at the same time. Find out which one opens first. At Shea Stadium , for example, Gate C opens two and a half hours prior to game time, whereas all other gates open only an hour and a half early. Excerpted with permission.