Mark Chay Jung Jun (simplified Chinese: 蔡荣俊; born 18 February 1982)[1] is a Singaporean Nominated Member of Parliament and freestyle swimmer who has represented the country at the Summer Olympics.

Chay was born and raised in Singapore, where he developed a passion for swimming at a young age.

Chay's notable abilities in the pool earned him a scholarship to Brigham Young University (BYU) in Provo, Utah.

[4] Chay's performance in the 2000 Sydney Olympic Games, positioned him as the top Asian swimmer in the 200m freestyle event during that year.

[7] Chay was appointed as Singapore's chef de mission for the 2014 Youth Olympic Games held at Nanjing, China and also one of the two deputy chefs de mission for the 2017 SEA Games held at Kuala Lumpur, Malaysia.