Fastest time to complete six 10-km marathon swims on six continents (male)
John Zemaitis, Joe Zemaitis
4:23:43 day(s):hour(s):minute(s):second(s)
Australia (Sydney)
Age Restriction: Applications for this record title will only be accepted if the applicant is 16 years of age or over.

The fastest time to complete six different 10-km (6.2-mile) marathon swims on six continents is 4 days 23 hours 43 minutes, achieved by brothers Joe and John Zemaitis (both USA) on 6–11 June 2023. Their first swim started in Cartagena, Colombia (South America) on 6 June 2023 at 07:35 local time (12:35 UTC) and their last swim ended in Sydney, Australia (Oceania) on 11 June 2023 at 22:18 local time (12:18 UTC). All six swims have been ratified by the Marathon Swimmers Federation.

The details of the Zeimatis' six swims were as follows:

- South America: Cartagena, Colombia - 6 June 2023, from Castillogrande to Blue Apple Beach, Isla de Tierra Bomba, 10.02 km in 2 hours 46 minutes 20 seconds.

- North America: Miami, Florida, USA - 7 June 2023, circumnavigation of Virginia Key in Biscayne Bay, 11.05 km in 3 hours 21 minutes 5 seconds.

- Africa: Casablanca, Morocco - 8 June 2023, from Plage David to Eden Island Beach, 10.2 km in 2 hours 41 minutes 47 seconds.

- Asia: Istanbul, Türkiye - 9 June 2023, from Maltepe to Moda in the Sea of Marmara, 10.03 km in 3 hours 19 minutes 39 seconds.

- Europe: Istanbul, Türkiye - 10 June 2023, from Atatürk Monument to Bakırköy in the Bosphorus Strait/Sea of Marmara, 11.02 km in 2 hours 59 minutes 24 seconds.

- Oceania: Sydney, Australia - 11 June 2023, from Cronulla Beach to the Captain Cook Monument, 10.31 km in 3 hours 15 minutes 38 seconds.

The female record is currently held by Jaimie Monahan (USA) who completed six swims across six continents in 15 days 8 hours 19 minutes, also starting in Cartagena, Colombia (South America) on 13 August 2018 but ending in New York City, USA (North America) on 28 August 2018.

The "Swim Brothers" have also achieved the longest tandem swim (multiple locations) when over a period of 25 days, from 20 July to 13 August 2022, they completed 50 marathon swims (10+ km), one in each of the 50 US states, logging a cumulative distance of 552.6 km (343.4 mi) over the course of their "Ultimate Swim-A-Thon".