By Sophie Kaufman on SwimSwam
2025 SWIM OPEN STOCKHOLM
- Saturday, April 12th – Tuesday, April 15th
- Stockholm, Sweden
- LCM (50m)
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- Entries/Live Results
- Livestream (Pay-To-Watch)
Lukas Märtens shocked the world yesterday at the 2025 Stockholm Open. He broke Paul Biedermann‘s super-suited world record in the 400-meter freestyle from 2009, becoming the first swimmer under 3:40 with a 3:39.96. Märtens improved the world record by .11 seconds and jumped from fourth on the all-time standings as he improved on his previous lifetime best of 3:40.33.
Courtesy: Stockholm Open
The 23-year-old Märtens jumped on the race from the start in Stockholm. It’s a familiar race strategy from him; we saw it during the Olympic final in Paris, where he claimed gold. It’s also the approach he used when he set his previous lifetime best of 3:40.33, when he flipped at the halfway mark just .26 seconds off Biedermann’s pace. However, that split pales in comparison to his opening 200 meters in Stockholm. He split 1:47.55 en route to his new world record, which put him nearly 3.5 seconds ahead of Biedermann’s opening split.
Biedermann came back exceptionally fast over the back half of his swim, which took down Ian Thorpe‘s world record of 3:40.08. However, Märtens was able to hold on with a 1:52.41 back half to get his hand under the world record and the 3:40 barrier.
Splits Comparison:
| Märtens’ New World Record | Biedermann’s Former World Record | Märtens’ Previous Best Time | |
| 50m | 24.75 | 26.29 | 25.00 |
| 100m | 27.15 (51.90) | 28.13 (54.42) | 27.37 (52.37) |
| 150m | 27.75 | 28.01 | 27.87 |
| 200m | 27.90 (55.65/1:47.55) | 28.59 (56.60/1:51.02) | 28.35 (56.22/1:48.59) |
| 250m | 28.28 | 27.76 | 28.21 |
| 300m | 28.18 (56.46) | 28.39 (56.15) | 28.01 (56.22) |
| 350m | 28.38 | 27.13 | 28.12 |
| 400m | 27.57 (55.95/1:52.41) | 25.77 (52.90/1:49.05) | 27.40 (55.52/1:51.74) |
| Total Time | 3:39.96 | 3:40.07 | 3:40.33 |
Read the full story on SwimSwam: Full Race Video: Lukas Märtens Breaks 400 Free World Record With A 3:39.96 At Stockholm Open