The 2009–10 Primera División season is the 91st of Costa Rica's top-flight professional football league.
Prior to the start of the season, the twelve teams were designated into groups based on their positions in the 2008-09 aggregate table.
The second round in the Invierno had the teams in each group play against each in a single round-robin format.
The winner of that tie will advance to the semifinals and play against one of the top teams from the groups.
The winners of that tie will advance to the finals, which will determine the tournament champion.