The nine heats consisted of between 1 and 5 swimmers, with the winner of the heat advancing along with the fastest loser from across the heats (all tied swimmers advanced in the case of equal times). There were two semifinals, intended to be of 5 swimmers each but one of which actually had 4 due to a withdrawal; the top 2 finishers in each semifinal (regardless of overall time) advanced to the 4-person final.
The nine heats included between 1 and 5 swimmers, with the victor of each heat advancing along with the fastest loser from across the heats (all tied swimmers advanced in case of equal times). There were two semifinals, planned to have 5 swimmers each but one actually having 4 due to a withdrawal; the top 2 finishers in each semifinal (regardless of overall time) qualified for the 4-person final.