After the Worlds, Wiffen will move his training base back to Ireland after a number of years studying and swimming at Loughborough University.
He will split his time between Dublin and America, where his twin Nathan will move to at the University of California later in the year, as he builds towards the next Olympics in Los Angeles in 2028.
The move will also mean the end of his successful partnership with coach Andi Manley, and Wiffen says he is undecided on who he will work with in the next stage of his career.
But for now his focus is on the World Championships, where he will add the 400 metre freestyle to the longer-distance 800m and 1500m.
Wiffen finished seventh in the 400m final in Doha before winning his two titles, admitting that “sparked something in me”.
“I don’t want to come in seventh place, I want to win. I’m adding it back in, I’m going to try and better seventh place as my goal.
“We’ll see how it goes. I’m hoping for a medal in it. It will be tough having now swam it for a year but I’m looking forward to it and the challenge.”
He added that the 400m would be treated as a “warm-up” for the longer events, but he is still aiming for a podium finish.
“This is going to sound weird because I try and treat the 400m as a warm-up. Even though I want a medal in it, we’re talking about trying to get that swim out of the way before the 800m.
“Sometimes you need that start-up race to have a really good race in your second one. For the 400m, it’s a warm-up race but I will give it the credit and I am trying to win a medal.”
