2025 World Athletics Relays – Mixed 4 × 400 metres relay

Prior to the competition, the records were as follows: == Qualification ==

On 10 November 2024, World Athletics announced the qualification system for the championships. The top 16 teams in each event at the 2024 Summer Olympic Games qualify for entry to the championships. The host country China will enter with one team in each event, regardless of any entry conditions. The remaining teams (up to 32 in total per event) will be determined through the top lists in the qualification period (1 January 2024 to 13 April 2025). == Program ==

All times are local (UTC+8). == Results ==

Heats (World Championships Qualifying Round 1) The heats were held on 10 May 2025, starting at 19:22 (UTC+8) in the evening. Qualification: First 2 of each heat () plus 2 fastest times () qualify to the 2025 World Athletics Championships and World Athletics Relays Final. Heat 1 Heat 2 Heat 3 Repechage Round (World Championships Qualifying Round 2) The repechage round were held on 11 May 2025, starting at 19:13 (UTC+8) in the evening. The repechage round consisted of all countries which did not qualify for the final. Qualification: First 3 of each heat qualify to the 2025 World Athletics Championships (). Heat 1 Heat 2 Final The final was held on 11 May 2025, starting at 21:03 (UTC+8) in the evening. == References ==