Leon Marchand Dominates 400 IM: Can Anyone Catch Up?

Leon Marchand has reigned supreme in the 400 IM for four years, crushing rivals with world records and Olympic gold. His latest French Championship win (4:04.56) reaffirms his dominance, leaving competitors like Japan’s Tomoyuki Matsushita (4:08) trailing far behind.

What makes Marchand so dominant?

Marchand’s breaststroke mastery sets him apart. In 2022, he overtook Carson Foster mid-race to win his first world title (4:04.28). Since then, he’s shattered Michael Phelps’ 400 IM world record (4:02.50 in 2023) and Ryan Lochte’s 200 IM mark. His Paris Olympics victory saw a 5.62-second gap over silver.

Who could challenge him?

Japan’s Matsushita (4:06.93 in 2025) is the closest threat, aiming to break Hagino’s Asian record. Ilia Borodin (4:09.16) and Duncan Scott (1:54.30 in 200 IM) have shown flashes but lack consistency. Marchand’s Texas teammate Shaine Casas (1:54.30) pushed him in the 200 IM but fell short.

What’s next for Marchand?

With the 2026 Pan Pacific Championships and Asian Games looming, Marchand remains the gold standard. His 400 IM times (4:02.50 WR, 4:04.56 in 2025) dwarf past legends like Phelps (4:03.84) and Lochte (4:05.18). Until someone cracks 4:06, Marchand’s reign seems unassailable.