Herman Willemse was inducted in the International Marathon Swimming Hall of Fame as an Honour Swimmer in 1963 and is also inducted in the International Swimming Hall of Fame as an Honoree. He was the first president of the World Professional Marathon Swimmers Federation.
Marathon Swimming Career
- the 30 km (19-mile) Traversée Internationale du lac St-Jean in Canada in 10 hours and 7 minutes in 1961, in 9 hours and 3 minutes in 1962 and in 8 hours and 32 minutes in 1963,
- the 36 km (22.5-mile) Around-the-Island Marathon Swim in Atlantic City, USA five times from 1960 to 1964,
- the 24 km (15-mile) Canadian National Exhibition race in 1961 and 1962,
- the 12.5 km (8-mile) Northumberland Strait race in 1964,
- the 37 km (23-mile) la Descente ou remontée du Saguenay in 6 hours and 15 minutes in 1966,
- four 16 km (10-mile) Tois Riviere Swims in 1961 to 1963 in Canada,
- the 58 km (36-mile) Maratón Acuática Internacional Santa Fe - Coronda in Argentina in 1963 with two third-place finishes in 1964 and 1966,
- 45 km (28-mile) Mar del Plato in Argentina,
- 42 km (26 miles) in the Suez Canal in Egypt,
- 88 km (54.6-mile) Hernandaras-Parana swim in Argentina and
- 32 km (20-mile) Maratona del Golfo Capri-Napoli in Italy.
When the World Marathon Swimming Championships, whereby points were awarded for performance in a series of races, started in 1964, he finished second to the International Marathon Swimming Hall of Fame Honour Swimmer Abou-Heif the next three years.