Events of national and international significance such as special anniversaries have been occasions for the issue of commemorative coins. There are no records to indicate that any such issues were made in Sri Lanka during the Portuguese, Dutch and British periods.
See also images and brief details of all Commemoratives on a single exhibit page.
See also Commemorative Currency Notes
1968 U.N. Food and Agriculture Organization - Grow More Food - Rs 2 coin
1976 Fifth Non-Aligned Summit Conference - Rs 5 coin + Proof - Rs 2 coin + Proof
1978 First Executive President J. R. Jayewardene - Rs 1 coin + Proof - RSS die coin - Gold frosted proof(NIP)
1981 Universal Adult Franchise - 50th Anniversary - Rs 5 coin
1981 Mahaweli Development Scheme inauguration = Rs 2 coin
1987 International Year of Shelter for the Homeless - Rs 10 coin - frosted coin(NIP)
1990 Central Bank of Sri Lanka - 40th Anniversary - Rs 500 coin - frosted proof
1991 South Asian Federation (SAF) Games V - Rs 500 coin - Rs 100 coin
1992 Second Executive President R. Premadasa - Rs 1 coin - frosted proof - Silver proof - Gold proof(NIP)
1993 Anubudu Mihindu Jayanthiya - 2300th Anniversary - Rs 500 coin
1995 United Nations - 50th Anniversary - Rs 5 coin + proof
1995 U.N. Food and Agriculture Organization - FAO 50th Anniversary - Rs 2 coin
1996 United Nations Children's Fund - UNICEF 50th Anniversary - Rs 1 coin
1998 Sri Lanka Independence - 50th Anniversary - Rs 5000 coin - Rs 1000 coin - Rs 10 coin - Rs 200 note and Flag pin
1999 Cricket World Cup - 1996 World Cricket Champions - Rs 1000 coin - Rs 5 coin
1999 Sri Lanka Army - 50th Anniversary - Rs 1 coin - frosted proof
2000 Central Bank of Sri Lanka - 50th Anniversary - Rs 1000 coin
2000 Sri Lanka Navy - 50th Anniversary - Rs 1 coin - frosted proof
2001 Sri Lanka Air Force - 50th Anniversary - Rs 1 coin
2001 Colombo Plan - 50th Anniversary - Rs 2 coin
2003 Syamopasampada - 250th Anniversary - Rs 5 - Sangharaja coin - Rs 5 - Nahimi coin
2006 Buddha Jayanthi 2550 B.E. - Rs 2000 coin - Rs 1500 coin - Rs 5 coin
2007 Cricket World Cup - Runners-Up - Rs 1000 coin - Rs 5 coin
2008 Employees Provident Fund (EPF) - 50th Anniversary - Rs 1000 coin - frosted proof(NIP) - Rs 2 coin
2009 Sri Lanka Customs Department - 200th Anniversary - Rs 200 coin
2009 Sri Lanka Army - 60th Anniversary - Rs 1000 - Cupro-Nickel coin - Silver coin
2010 Central Bank of Sri Lanka - 60th Anniversary - Rs 5000 coin
2011 Sri Lanka Air Force - 60th Anniversary - Rs 2 coin
2011 - Sambuddhatva Jayanti 2600 - Rs 1000 coin - Rs 10 coin
2011 - People's Bank 50th Anniversary - Rs 1000 coin
2011 - Ananda College 125th Anniversary - Rs 2000 coin
2012 - Sri Lanka Scout Centenary - Rs 2 coin
2012 - Sri Lanka - Japan 60 Years. - Rs 1000 coin
See also Historical Background by Tuan Sallay, and some of my comments.
I thank the former Superintendent of Currency of the Central Bank of Sri Lanka for providing me in 2001 with the mint figures of issues since 1985 and T. M. U. Sallay for older figures.
In commemorative Lankan coins the only exceptions to having all of the text in all three languages are the first Buddhist commemorative coins issued in 1957, the President Jayawardena coin issued in 1978 which have the name of the country only in Sinhala. The only other exceptions are the World Cup Cricket coins which has the names of the dozen participating nations only in English, and the 50th Anniversary of Independence Rupees Ten coin which has the incuse lettering on edge only in English.
All coin designs adopted after 1980 have the country name in all three languages, and after 1995 even ensure the font size of text is also the same. However all of the regular circulation issues since 1963 which are based on designs adopted before 1980 have the name of the country only in Sinhala. Therefore the one Rupees and smaller denomination coins issued even in 2005 do not have the name of the country in Tamil or English.
LakdivcCoins Collection website.