The 2018 Pan Pacific Swimming Championships, a long course (50 m) event, was held in Tokyo, Japan, from 9 to 14 August 2018.

[1] Unlike the World Championships and Olympic Games, nations can enter as many people as they like in the preliminaries of each event (in most international meets, only two swimmers from each nation are permitted).

Prior to FINA's creation of semi-finals in the late 1990s, a total of 3 swimmers per country could qualify for the final and consolation heats of an event, with no more than 2 swimmers per country in a final or consolation.

For relays, each country may enter up to one team in each relay event to swim in the final heat and count toward the team score.

Countries may also enter a “B” relay that will swim in a preceding heat.