With the completion of the swimming pool in 1986, serious swimming was introduced. Initially there were no awards of Colours and Lions. However by 1988, swimmers took part in Zonal and All-Island Competitions.
In 1990 Trinity entered the National Schools Games and outstation meets. Hence awarding of colours was initiated.
In 1991, college was ready with strong swimmers to contest in the novices meet.
Swimming became an integral part of education at Trinity. It was taught from an early age at kindergarten. A swimming period was allocated from grade 1 to 5 as part of the student's co-curricular activities.
In the years to come, swimmers took part in various traditional meets and swimming and diving championships such as
- Commonwealth Games
- South Asian Games
- Asian Games
- Asian Youth Games
- National Short Course Swimming Championships
- National Pentathlon Championships
- National Sports Festivals
- Novices Swimming Championships
Age groups at present that take part in tournaments are as follows:
- Under 11
- Under 13
- Under 15
- Under 17
- Under 18
- Under 19
In the year 1991 A Wickramaratna established a new record at the Outstation School Championship.
In 1999 H.T.A Perera and S.DE Silva were selected to represent the Sri Lankan team in International Tournaments.
In 2005 following members were selected to the SAAF pool.
- H.B Hullugalla
- C.L.B. Wijeratne
- H.B Unamboowa
Chetiya Wijeratne was awarded school colours, Sri Lanka Aquatic School Colours and was awarded Trinity Lion. He was rewarded with Central Province Colours as well.
In 2008 and 2009 Heshan Bandara Unamboowa, Captain 2010, Lion, Olympian brought honour to Sri Lanka and Trinity College by winning a medal at the Asian School Swimming Championships for the 1st time in Sri Lanka history.
He also captained the Sri Lankan Team. Further Heshan captained the Sri Lankan team at the 13th FINA World Championships in 2009 held in Rome, Italy and established two new National Records.
In the same year Heshan won the National Age Group Championship under 19, for the 10th consecutive year, establishing seven new National Age Group records.
He won the Best Sportsman award for the year 2011, at the National School Colours Award Ceremony.
S.K.A Hulangamuwa was awarded the Swimming Lion in 2010.
Sineru Auwardt, Aishwarya Shiek, Travers Edussuriya and Migara Hulangamuwa won National Level Championships.
T. E.Edussuriya and M.Hulangamuwa won National School Colours for the year 2011.
In 2018 there were notable achievements at all Island levels. H.O.C.Hiripitiya, T.K.Karunathilake, M.Jayasinghe won the Central Province Colours.