The athletics competition at the 2028 Olympics in Los Angeles will take place in the first week, with swimming moved to the second week in "a historic shift of the competition schedule" designed to give the Games a strong start.
World Athletics and LA organizers announced the "unprecedented move" on Friday. Up to now, and including the upcoming Paris Olympics, swimming was held in the first week and athletics in the second - with an overlap on the middle weekend.
The change was explained with the aim "at optimising the venue master plan" for the July 14-30, 2028, Games.
The athletics competition is set to be held at LA Memorial Coliseum which is also the venue for the opening and closing ceremonies.
Swimming is scheduled for the home stadium of American Football teams San Diego Chargers and LA Rams, with a record 38,000 seats available. Parts of the ceremonies will also take place there, LA organizers said.
"We are excited to support this visionary timetable change for LA28," World Athletics president Sebastian Coe said.
"This change underscores our commitment to innovation in athletics and elevating the global profile of our athletes. By prioritising athletics in the first week, the Games will witness the most thrilling of starts, captivating audiences worldwide and setting the stage for an unforgettable Olympic journey for global audiences."
LA28 chief athlete officer Janet Evans said: "We believe the positive effects of this change will extend beyond the two sports involved, strengthening the LA28 Games as a whole and ultimately benefiting all sports in the LA28 sport programme."
The only exception are the men's and women's marathons which will stay at their final weekend slot, and their medal ceremonies remain part of the closing ceremony.