Exhibit 99.1 Contact: Evan Bertrand Vice President, Investor Relations and Treasurer +1-972-595-5180 investorrelations@sftp.com Six Flags Reports Fourth Quarter and Full Year 2023 Performance ARLINGTON, Texas — February 29, 2024 — Six Flags Entertainment Corporation (NYSE: SIX), the world's largest regional theme park company and the largest operator of water parks in North America, today reported fourth quarter Revenue of $293 million, Net Loss of$22 million, and Adjusted EBITDA of $98 million. For the fu ...