|Western border (nautical)||180 degrees|
|Eastern border (nautical)||172.5 degrees W|
|Date-time group (DTG)||Y|
As standard time (all year round)
UTC−12 is a nautical time zone comprising the high seas between 180° and 172°30′W longitude, and the time is obtained by subtracting twelve hours from Coordinated Universal Time. Ships using this time are the last to begin each calendar day.
Characteristics of the time zone which observes UTC-12
A number of inhabited islands lie within the longitudinal limits of this time zone, but none of them keeps the date and time of UTC-12. Instead, they keep the time and date (or just the date) of one of the neighbouring zones, usually because they belong, politically, to an island group whose other members lie mostly in the neighbouring time zone.
Since the International Date Line West (IDLW) time-zone represents the last place on earth where any date exists, it is sometimes used for deadlines and referred to as Anywhere on Earth (AoE). This means that if the deadline has not passed in the UTC–12 zone, the deadline has not yet passed.