UTC+13:00 is an identifier for a +13 hour time offset from UTC.
The Republic of Kiribati introduced a change for its eastern half on 1 January 1995, from time zones −11 and −10 to +13 and +14, to avoid having the country divided by the International Date Line.
Tonga has been on UTC+13 for many years. Daylight saving time was used in the southern summer seasons from 1999 to 2002.