British Swimming chief executive Jack Buckner will leave his position later this year to take up the same role at UK Athletics, both governing bodies said on Thursday.
Former middle-distance runner Buckner, a European champion and world bronze medallist, joined British Swimming in 2017 and oversaw record success for its athletes at last year's Tokyo Olympics where they won eight medals, including four golds.
The 60-year-old will replace interim UK Athletics chief Mark Munro, who took over after Joanna Coates resigned in October.
"The last five years have been a wonderful adventure with British Swimming," Buckner said in a statement. "The resilience and determination shown over the pandemic was extraordinary. I'll never forget the stunning results in Tokyo."
"Athletics has been a huge part of my life since I was a teenager and I can't wait to be trackside later in the year," he added.
Buckner, who was previously in charge at British Triathlon, will lead the build-up to the 2024 Olympics and Paralympics while Munro will remain with the organisation as its new chief operating officer.
The British athletics team left the Olympics without a gold for the first time since 1996 and were stripped of the men's 4x100m relay silver after Chijindu Ujah's doping violation, which reduced their tally of medals to five.