MLB’s traditional trade-deadline date from the 1986 Basic Agreement era was July 31.
For decades, July 31 served as baseball’s main midsummer cutoff for trades involving players on major-league reserve lists. The date replaced the June 15 deadline that had governed since 1923, reflecting MLB’s changing competitive and roster-building practices.
The wording can cause confusion because July 31 was later described as the “non-waiver” Trade Deadline. Before 2019, teams could still make certain August trades after players cleared trade waivers, so July 31 was not always the final date on which any transaction could occur. That waiver-trade period was abolished before the 2019 season, leaving one principal in-season trade cutoff.
The clock has also changed: historically, the deadline was commonly associated with midnight Eastern Time, while modern MLB deadlines are set by the league and have often used a 4 p.m. Eastern cutoff. Thus, the date is the key historical answer, even though the exact time and calendar day can vary in a particular season.