Nicolas Fink (born July 3, 1993) is an American competitive swimmer. He is a five-time world champion in breaststroke events and a 2024 Olympic Silver Medalist in the 100 meter breaststroke. He is a world record holder in the short course 4×100 meter medley relay and 4×50 meter mixed medley relay. He is the Americas record holder in the short course 50 meter breaststroke, 100 meter breaststroke, and 200 meter breaststroke as well as the American record holder in the long course 50 meter breaststroke. In the 50 meter breaststroke, he won the World Short Course titles in 2021 and 2022 and World Long Course title in 2022. In the 100 meter breaststroke, he is the 2022 World Short Course gold medalist. In the 200 meter breaststroke, he is the 2021 World Short Course gold medalist.

Fink grew up in Morristown, New Jersey and attended Pingry School. He started dreaming about being an Olympian while watching swimming on television as a kid.

Fink has trained with a number of swim teams around the world, including Saint Petersburg Aquatics, where he swam alongside athletes such as Robert Finke, Joshua McQueen, and Melanie Margalis. Collegiately, Fink competed for the Georgia Bulldogs of the University of Georgia, signing his official letter of intent in fall 2010. He went to school to study engineering and works in a full-time engineering job while swimming.

Fink competed at his first US Olympic Trials in 2012 at the 2012 USA Swimming Olympic Trials held in Omaha, Nebraska in June and July. He placed 11th in the 100 meter breaststroke with a time of 1:01.14, 17th in the 200 meter breaststroke with a 2:13.89, and 26th in the 200 meter individual medley with his time of 2:03.69. He did not qualify for the 2012 US Olympic Team in any of the events he raced.

Fink broke out onto the national scene after he placed 2nd in the 2013 US National Championships in the 100m breaststroke with a time of 1:00.24. Fink also placed 3rd in the 200m breaststroke and 6th in the 50m breaststroke.

At the 2013 World Aquatics Championships in Barcelona, Fink placed 8th in the final of the 100m breaststroke with a time of 1:00.10.

Fink made the US team for the 2014 Pan Pacific Championships in Gold Coast, Australia, with his performances at the 2014 National Championships in Irvine, California. In the final of the 200 meter breaststroke, Fink swam a 2:08.94, winning the silver medal as one of only two competitors to swim under 2:10.00 in the final with the other being Yasuhiro Koseki of Japan who won the gold medal. Fink's swims at both championships earned him a spot on the US National Team in swimming for the 2014—2015 year, making him one of twelve student athletes from the University of Georgia to be named to the year's team. His race in the 200 meter breaststroke at the 2014 Pan Pacific Championships also earned him a nomination for USA Swimming's Golden Goggle Award for "Male Race of the Year".

At the 2016 US Olympic Trials in Omaha, Nebraska, Fink placed 7th in the 100 meter breaststroke final with a time of 1:00.39 and placed 7th in the 200 meter breaststroke with a time of 2:11.55 in the final. This was the second time Fink competed at the US Olympic Trials as well as the second time he did not make the US Olympic Team.