Longest tandem swim (multiple locations)

Over a period of 25 days, from 20 July to 13 August 2022, brothers Joe and John Zemaitis (both USA, aka the Swim Brothers) completed 50 marathon swims (10+ km), one in each of the 50 US states, logging a cumulative distance of 552.6 kilometres (343.4 miles) over the course of their "Ultimate Swim-A-Thon".

The Swim Brothers started their Ultimate Swim-A-Thon in Hawaii, swimming from Makaha Beach to Keawaula Beach on Oahu, before travelling on to Alaska, then starting their tour of the mainland USA in Nevada. The swimathon ended in their home state of Arizona, with a 10.38-km (6.4-mi) swim in Lake Powell. They also covered more than 11,000 mi (17,700 km) driving an RV between the swim locations in the contiguous USA.

The longest single stage swam was 17.16 km (10.66 mi) in the Willamette River in Portland, Oregon, on 23 July 2022, four days into the challenge.

On some legs, they swam in the same body of water but would start and end in different states (e.g, on Day 3 they completed their Nevada and California swims both in Lake Tahoe, which straddles the two states, completing a marathon swim on either side of the state border. The Minnesota swim in Lake Minnewaska scheduled for Day 7 had to be postponed to the following day owing to stormy weather and risk of lightning strikes.

The challenge raised more than $10,000 on behalf of the USA Swimming Foundation.