Time in Sri Lanka since 15 April 2006 is officially represented by the Sri Lanka Standard Time (SLST, UTC+05:30).
Contents
Historic UTC offsets were:
Daylight saving time
In history daylight saving time was used too.
IANA time zone database
The IANA time zone database contains one zone for Sri Lanka in the file zone.tab, named Asia/Colombo.
References
Time in Sri Lanka Wikipedia(Text) CC BY-SA