Learning Ice Hockey Rules: What Are Coincidental Penalties?

The game of ice hockey can be a tricky game to understand for some people who are not familiar with the game. One aspect of the game that tends to confuse a fair number of people is coincidental penalties. A coincidental penalty occurs when two or more players from opposing teams take a penalty at the same time. It does not matter if the penalty is a minor, double minor, or a major penalty, as they can all potentially be coincidental penalties. Furthermore, the current on ice strength or either team does not affect the coincidental penalties, as they can occur even if one of the teams is currently serving a penalty for another reason.

The most common occurrences of coincidental penalties occur during a stoppage of play when a skirmish takes place. In this case, players often escalate their pushing and shoving into an action deserving a penalty. For example, if two players, one on each team, receives a two minute minor penalty for roughing, then both players will be taken to the penalty box and will have the same amount of penalty time. Instead of punishing both teams for the actions of their respective players, the teams will remain at full strength, meaning they will both have five players on the ice.

The players receiving the coincidental penalties must serve the entire duration of their penalties. Additionally, they must continue to stay in the penalty box and cannot return to play until there has been a stoppage of play for some reason. It does not matter how long it takes, there must be a break in play in order for the players to leave the penalty box. The reason for this is due to the fact that both teams are currently playing at full strength. If either player would happen to leave the penalty box before a stoppage of play, then the team would have too many players on the ice at a time, resulting in a minor penalty for too many men on the ice. As soon as the stoppage of play take place, the players are free to exist the penalty box and can return either directly to the game or can go back to their respective team benches.
Sources:

USA Hockey Rules

Composite Hockey Sticks