SeaWorld San Antonio and the two Texas Six Flags parks will continue to limit capacity and require face masks.
Cedar Fair says it will fill 45,000 seasonal positions across its parks for the 2021 season.
On the plus side, per capita revenue, admissions, and in-park spending increased in 2020.
The park will be taken over by Herschend Family Entertainment, the company behind Dollywood and Silver Dollar City.
Several parks' reopening dates depend on government COVID-19 guidelines.
The theme park chain lost $590 million in 2020, but expects 2021 to be an improvement.
Six Flags America and California's Great America are helping facilitate COVID-19 vaccine distributions.
Guests were briefly being seated in every row at Universal's Bourne Stuntacular show.