The casino will be the last of Caesars’ properties to reopen in the US and Canada following COVID-19 forced closures in March.
The hotel will accommodate weekend stays and the gaming floor will be open seven days a week.
Commenting on the opening, Anthony Carano, president and chief operating officer of Caesars, said: “The past nine months have been filled with challenges, as well as opportunities including the merging of our two gaming companies to form the new Caesars Entertainment.
“We recognize the incredible effort it has taken to reopen our resorts and get us to this important milestone, and we look forward to welcoming our Team Members and Guests back to Rio with their health and safety still top of mind."
On opening day, the Rio casino will also debut its newly branded William Hill sportsbook, offering sports betting kiosks and in-play wagering.
In September this year, Caesars secured a $3.72bn deal for the acquisition of William Hill. The terms of the deal will see Caesars pay $3.57 for each share in the originally UK-based bookmaker.
A statement from Caesars described the agreement as a “historic acquisition.” The operator expects the combined sports and online gaming business in the US to generate between $600m to $700m in net revenue for the full-year 2021 on a pro-forma basis.