# 2021 FINA World Swimming Championships (25 m) – Mixed 4 × 50 metre medley relay

The Mixed 4 × 50 metre medley relay competition of the 2021 FINA World Swimming Championships (25 m) was held on 18 December 2021.

## Records

Prior to the competition, the existing world and championship records were as follows.
| World record | Netherlands (NED) | 1:36.18 | Kazan, Russia | 7 November 2021 |
| Competition record | United States (USA) | 1:36.40 | Hangzhou, China | 13 December 2018 |
The following new records were set during this competition:
| Date | Event | Name | Nation | Time | Record |
| 18 December | Final | Kira Toussaint (26.21) Arno Kamminga (25.40) Ranomi Kromowidjojo (24.36) Thom de Boer (20.23) | Netherlands | 1:36.20 | CR |

## Results
### Heats

The heats were started at 11:18.
| Rank | Heat | Lane | Nation | Swimmers | Time | Notes |
| 1 | 4 | 3 | United States | Shaine Casas (23.15) Nic Fink (25.70) Kate Douglass (24.60) Katharine Berkoff (24.29) | 1:37.74 | Q |
| 2 | 4 | 4 | Russian Swimming Federation | Pavel Samusenko (23.05) Andrei Nikolaev (26.33) Arina Surkova (24.94) Rozaliya Nasretdinova (23.67) | 1:37.99 | Q |
| 3 | 5 | 4 | Netherlands | Tessa Giele (26.52) Arno Kamminga (25.82) Nyls Korstanje (22.04) Kim Busch (24.00) | 1:38.38 | Q |
| 4 | 3 | 4 | Italy | Michele Lamberti (23.44) Benedetta Pilato (29.78) Silvia Di Pietro (24.99) Leonardo Deplano (20.84) | 1:39.05 | Q |
| 5 | 4 | 5 | France | Yohann Ndoye Brouard (23.74) Antoine Viquerat (26.18) Marie Wattel (25.31) Charlotte Bonnet (24.05) | 1:39.28 | Q |
| 6 | 5 | 3 | Greece | Apostolos Christou (23.27) Maria Drasidou (30.14) Anna Ntountounaki (25.55) Andreas Vazaios (21.32) | 1:40.28 | Q, NR |
| 7 | 3 | 5 | Finland | Ronny Brännkärr (24.18) Olli Kokko (26.14) Laura Lahtinen (26.00) Fanny Teijonsalo (23.98) | 1:40.30 | Q |
| 8 | 5 | 5 | Belarus | Viktar Staselovich (24.13) Alina Zmushka (30.25) Grigori Pekarski (22.29) Nastassia Karakouskaya (24.35) | 1:41.02 | Q |
| 9 | 3 | 3 | Turkey | Doruk Tekin (23.98) Emre Sakçı (25.23) Nida Eliz Üstündağ (27.17) Ekaterina Avramova (25.00) | 1:41.38 | |
| 10 | 1 | 6 | Brazil | Gabriel Fantoni (23.27) Jhennifer Conceição (29.59) Nicholas Santos (22.55) Gabrielle Roncatto (26.03) | 1:41.44 | |
| 11 | 1 | 7 | South Korea | Won Young-jun (23.91) Moon Jae-kwon (26.39) Park Ye-rin (26.17) Jeong So-eun (25.02) | 1:41.49 | NR |
| 12 | 5 | 6 | Estonia | Armin Evert Lelle (24.22) Eneli Jefimova (30.21) Daniel Zaitsev (22.57) Maria Romanjuk (25.91) | 1:42.91 | |
| 13 | 1 | 3 | Hong Kong | Lau Shiu Yue (24.21) Ng Yan Kin (27.81) Sze Hang Yu (26.32) Tam Hoi Lam (25.05) | 1:43.39 | |
| 14 | 4 | 6 | Slovakia | Ádám Halás (24.88) Tomáš Klobučník (27.17) Zora Ripková (26.49) Lillian Slušná (25.16) | 1:43.70 | |
| 15 | 1 | 1 | Thailand | Tonnam Kanteemool (25.22) Jenjira Srisaard (30.61) Navaphat Wongcharoen (23.81) Kornkarnjana Sapianchai (25.65) | 1:45.29 | NR |
| 16 | 3 | 0 | Argentina | Florencia Perotti (29.41) Martina Barbeito (30.99) Santiago Grassi (23.29) Guido Buscaglia (21.64) | 1:45.33 | |
| 17 | 2 | 5 | Jamaica | Keanan Dols (25.75) Alia Atkinson (29.14) Sidrell Williams (24.60) Zaneta Alvaranga (26.13) | 1:45.62 | |
| 18 | 1 | 4 | Luxembourg | Max Mannes (25.21) Julien Henx (27.88) Julie Meynen (27.30) Monique Olivier (25.73) | 1:46.12 | |
| 19 | 3 | 2 | Dominican Republic | Elizabeth Jiménez (29.36) Josué Domínguez (26.39) Krystal Lara (28.13) Denzel González (22.91) | 1:46.79 | |
| 20 | 3 | 6 | Andorra | Mònica Ramírez (30.04) Patrick Pelegrina (28.29) Tomàs Lomero (23.56) Nàdia Tudó (26.90) | 1:48.79 | NR |
| 21 | 2 | 3 | Aruba | Elisabeth Timmer (29.62) Bransly Dirksz (29.97) Mikel Schreuders (24.09) Chloe Farro (26.39) | 1:50.07 | |
| 22 | 2 | 4 | Netherlands Antilles | Bianca Mitchell (33.29) Jadon Wuilliez (26.68) Samantha Roberts (28.46) Stefano Mitchell (22.15) | 1:50.58 | |
| 23 | 3 | 1 | Senegal | Steven Aimable (25.01) Adama Niane (31.67) Oumy Diop (26.95) Jeanne Boutbien (27.32) | 1:50.95 | |
| 24 | 5 | 8 | Azerbaijan | Fatima Alkaramova (31.00) Rashad Alguliyev (29.94) Ramil Valizade (24.09) Mariam Sheikhalizadeh (26.04) | 1:51.07 | |
| 25 | 2 | 9 | Uganda | Avice Meya (31.51) Tendo Mukalazi (30.19) Jesse Ssengonzi (24.04) Kirabo Namutebi (25.93) | 1:51.67 | |
| 26 | 2 | 6 | Faroe Islands | Elisabeth Erlendsdóttir (29.64) Bartal Erlingsson Eidesgaard (29.21) Johan Nónskarð Dam (27.04) Alisa Bech Vestergård (26.64) | 1:52.53 | |
| 27 | 1 | 5 | Cayman Islands | Lauren Hew (29.64) Alison Jackson (34.45) Liam Henry (24.82) Richard Allison (23.63) | 1:52.54 | |
| 28 | 3 | 8 | Mongolia | Khuyagbaataryn Enkhzul (30.37) Batbayaryn Enkhtamir (30.06) Batmönkhiin Jürmed (25.83) Batbayaryn Enkhkhüslen (26.52) | 1:52.78 | |
| 29 | 3 | 9 | Angola | Catarina Sousa (30.27) Salvador Gordo (30.32) Lia Lima (28.91) Henrique Mascarenhas (23.34) | 1:52.84 | |
| 30 | 5 | 2 | Armenia | Ani Poghosyan (32.47) Varsenik Manucharyan (34.37) Artur Barseghyan (23.13) Vladimir Mamikonyan (23.09) | 1:53.06 | |
| 31 | 4 | 7 | Saint Lucia | Terrel Monplaisir (28.31) Naima Hazell (33.67) Jayhan Odlum-Smith (24.25) Mikaili Charlemagne (27.01) | 1:53.24 | |
| 32 | 4 | 0 | Seychelles | Aaliyah Palestrini (30.41) Simon Bachmann (29.40) Mathieu Bachmann (25.48) Khema Elizabeth (28.39) | 1:53.68 | |
| 33 | 2 | 1 | Mauritius | Gregory Anodin (27.23) Jonathan Chung Yee (29.66) Alicia Kok Shun (30.99) Tessa Ip Hen Cheung (26.92) | 1:54.80 | |
| 34 | 2 | 2 | Malawi | Ammara Pinto (32.60) Filipe Gomes (28.33) Muhammad Moosa (31.31) Jessica Makwenda (29.01) | 2:01.25 | |
| 35 | 2 | 0 | Maldives | Hamna Ahmed (33.95) Mohamed Aan Hussain (34.39) Ali Imaan (27.30) Aishath Sausan (30.33) | 2:05.97 | |
| | 5 | 7 | Switzerland | Roman Mityukov (24.42) Lisa Mamié (30.52) Noè Ponti Alexandra Touretski | DSQ | |
| | 1 | 2 | Guam | | DNS | |
| | 2 | 7 | Cape Verde | | DNS | |
| | 2 | 8 | Nigeria | | DNS | |
| | 3 | 7 | Tanzania | | DNS | |
| | 4 | 1 | Turks and Caicos Islands | | DNS | |
| | 4 | 2 | Albania | | DNS | |
| | 4 | 8 | Peru | | DNS | |
| | 4 | 9 | Northern Mariana Islands | | DNS | |
| | 5 | 0 | Mexico | | DNS | |
| | 5 | 1 | North Macedonia | | DNS | |
| | 5 | 9 | Zimbabwe | | DNS | |

### Final

The final was held at 19:55.
| Rank | Lane | Nation | Swimmers | Time | Notes |
| | 3 | Netherlands | Kira Toussaint (26.21) Arno Kamminga (25.40) Ranomi Kromowidjojo (24.36) Thom de Boer (20.23) | 1:36.20 | CR |
| | 4 | United States | Shaine Casas (23.16) Nic Fink (25.82) Claire Curzan (24.85) Abbey Weitzeil (23.21) | 1:37.04 | |
| | 6 | Italy | Lorenzo Mora (23.28) Nicolò Martinenghi (25.60) Elena Di Liddo (24.91) Silvia Di Pietro (23.50) | 1:37.29 | |
| 4 | 5 | Russian Swimming Federation | Pavel Samusenko (22.95) Kirill Strelnikov (26.02) Arina Surkova (25.14) Maria Kameneva (23.33) | 1:37.44 | |
| 5 | 8 | Belarus | Grigori Pekarski (23.59) Ilya Shymanovich (24.93) Anastasiya Shkurdai (25.23) Nastassia Karakouskaya (24.22) | 1:37.97 | |
| 6 | 2 | France | Mewen Tomac (23.37) Antoine Viquerat (25.96) Béryl Gastaldello (25.17) Marie Wattel (23.78) | 1:38.28 | |
| 7 | 7 | Greece | Apostolos Christou (23.34) Maria Drasidou (30.04) Anna Ntountounaki (25.01) Andreas Vazaios (21.12) | 1:39.51 | NR |
| 8 | 1 | Finland | Ronny Brännkärr (24.05) Olli Kokko (26.05) Laura Lahtinen (25.88) Fanny Teijonsalo (24.48) | 1:40.46 | |