Imre Szénási is an open water swimmer from Hungary who was inducted in the International Marathon Swimming Hall of Fame in 1973 as an Honour Swimmer. He held several world records for longest lake and river swims and completed a 24-hour Swim six times during his career.
- In 1958, he finished second at the World Championships in the amateur category.
- In 1958, he competed in the 36 km Maratona del Golfo Capri-Napoli in Italy.
- In 1959, he set a Hungarian record with a 130 km (88.7-mile) river swim from Medveďov in Slovakia to Budapest, Hungary in 19 hours 45 minutes
- In 1961, he set a record with a 76 km (47.2-mile) lake swim from Balatonkenese to Keszthely in Lake Balaton, Hungary in 36 hours 29 minutes.
- In 1963, he finished
- In 1964, he swam 77 km (47.8 miles) in the Danube River from Budapest to Dunaujvaros, Hungary in 13 hours 55 minutes.
- In 1966, he swam 219 km (136 miles) down the River Tisza from Tiszasüly to Szeged in Romania and Hungary in 44 hours 50 minutes.
- On 2 September 1967, he set a record with a 241 km (149.7-mile) river swim from Bratislava, Slovakia to Budapest, Hungary in 41 hours 40 minutes at the age of 35.
- In 1972, he set a record with a 240 km (149.1-mile) river swim from Kiskore to Szeged in 45 hours 57 minutes.
- In 1973, he set a record with a 250 km (155.3-mile) river swim from Vienna, Austria to Budapest, Hungary in 50 hours.