The Men's 400 metre freestyle event at the 2013 Southeast Asian Games took place on 14 December 2013 at Wunna Theikdi Aquatics Centre.
There were 12 competitors from 7 countries who took part in this event. Two heats were held. The heat in which a swimmer competed did not formally matter for advancement, as the swimmers with the top eight times from both field qualified for the finals.
Swimming at the 2013 Southeast Asian Games – Men's 400 metre freestyle Wikipedia
All times are Myanmar Standard Time (UTC+06:30)
Prior to this competition, the existing world, Asian, and Southeast Asian Games records were as follows.