Six Flags Magic Mountain in Valencia, Calif. and Universal Studios Hollywood in Universal City will require proof of complete COVID-19 vaccination or negative virus test results from all guests, according to reports. 

The theme parks adjusted guidelines to comply with recent Los Angeles County Department of Public Health rules that require outdoor "mega events" with guests of more than 10,000 people to add health procedures. 

Six Flags will be requiring guests to display their vaccination or negative test results on certain days. Universal Studios requires guests always to be prepared to show proof of their vaccine or test results. Verification, however, will take place when needed based on theme park attendance. 

In addition, Six Flags will be partnering with CLEAR, an app that allows employees or attendees to upload proof of vaccination, negative COVID-19 tests, or fill out health surveys.