The Championship Round was two competitions: Taça Guanabara and Taça Rio. The twelve clubs were into two groups of six, Group A and Group B. The traditional "big four" teams of Rio de Janeiro (
Flamengo,
Botafogo,
Fluminense, and
Vasco da Gama) were separated with two teams placed in each group. Each round had its own four-team playoff featuring the top two teams of each group. The Taça Rio was followed by a four-team Final playoff featuring the top four teams of the combined table across both competitions (the competition playoff champion(s) automatically qualified for the Final playoff). ===
Taça Guanabara === The Taça Guanabara was played from 16 January 2018 to 4 February 2018. It was a single round-robin format with each team playing one match with the teams of their own group. The two top point teams qualified for the knockout stage of the competition. The champion of Taça Guanabara qualified to the Final Stage.
Knockout stage Semi-finals ----
Final ===
Taça Rio === The Taça Rio tournament was from 19 February 2018 to 18 March 2018. Group A and Group B remained the same as in Taça Guanabara, but each team played a single match round-robin against the teams of the other group. The top two teams in points in each group qualified for the knockout stage of the competition. The champion of Taça Rio qualified to the Final Stage.
Knockout stage Semi-finals ----
Final == Relegation playoffs ==