IANA tz database · zone identifier

Asia/Seoul

The IANA tz database identifier for Korean Standard Time in South Korea. Store this string — not the abbreviation, not the offset — and your timestamps stay correct forever.

UTC+09:00Abbreviation KSTNo daylight saving
Time in Asia/Seoul☀ Daylight
08:00:34
Thursday, October 15, 2026
Offset
UTC+09:00
Abbreviation
KST
DST
No DST

Current offset

UTC+09:00

same year-round

Abbreviation

KST

used year-round

DST behaviour

None

one offset all year

Country

🇰🇷 South Korea

ISO 3166: KR · view country page →

Using this identifier

The string to put in your code.

Asia/Seoul is the identifier to use in code and config for this region. Every modern language, database, and OS resolves it through the same tz database, so the examples here behave identically everywhere.

Avoid storing KST or +09:00 — abbreviations are ambiguous and fixed offsets can't follow rule changes.

// format a date in this zone
new Intl.DateTimeFormat('en-US', {
timeZone: 'Asia/Seoul',
dateStyle: 'full', timeStyle: 'long'
}).format(new Date());

Offset & DST behaviour

One offset,
38 years.

Asia/Seoul has kept UTC+09:00 year-round since 9 October 1988 — no daylight saving and no offset changes on record since. It is among the most stable identifiers in the database.

Every offset this zone has kept

+08:27:52UTC+09:00 · UNCHANGED 9 October 1988 NOW

Keeping this offset since

9 October 1988

Next transition

None scheduled

no DST rules exist for this zone

Safe to assume

Local = UTC + 9h, always

…but store the identifier anyway

Technical record

The database entry, in full.

source: IANA tz database · release 2026d

IdentifierAsia/Seoul
ISO country codeKR🇰🇷 South Korea
Reference coordinates37.55°N, 126.97°Etz database reference point
Standard offsetUTC+09:00abbreviation KST
Daylight offset—no daylight saving time
tzdb release2026ddata current as of this IANA release

Where it applies

All of South Korea, one clock.

Looking for travel-friendly info? See Seoul or Korean Standard Time.

🇰🇷
South Korea

51M people, one time zone. The whole country resolves to Asia/Seoul.

Country page →
🇰🇷 Seoul
08:00
08:00:34 · KST
pop. 9.7MKST
🇰🇷 Busan
08:00
08:00:34 · KST
pop. 3.5MKST
🇰🇷 Incheon
08:00
08:00:34 · KST
pop. 3MKST

Related identifiers

Nearby in the database.

Same zone group · Korean Standard Time

other identifiers keeping KST

Same offset · UTC+09:00

other zones keeping this offset right now

Frequently asked questions

Answers specific to this identifier — generated from the database record. Can't find what you need? Email [email protected].

What UTC offset is Asia/Seoul?
Asia/Seoul is UTC+09:00, year-round. The offset never changes because the zone does not observe daylight saving time.
Does Asia/Seoul observe daylight saving time?
No. Asia/Seoul stays on UTC+09:00 all year, as it has since 9 October 1988.
Which country uses Asia/Seoul?
South Korea. The identifier covers the whole country.
Is Asia/Seoul the same as KST?
Asia/Seoul is one of the IANA zones that keeps Korean Standard Time (KST). Use Asia/Seoul in software — KST is a human-friendly label, not a valid identifier.

Free · Developer API

This zone, as JSON.

Its live offset, abbreviation and DST status, plus its coordinates and country, from one endpoint.

GET /v1/timezones Live

Also in the API: time zones by coordinates, conversions that flag daylight saving gaps, and abbreviations decoded.

Get your free API key → All endpoints Plans and pricing

Moving off WorldTimeAPI? Our drop-in replacement needs no key.

// this identifier, resolved live
GET /v1/timezones/Asia/Seoul
{
"data": {
"iana": "Asia/Seoul",
"observes_dst": false,
"country": { "code": "KR", "name": "South Korea" },
"current": {
"utc_offset": "+09:00",
"abbreviation": "KST",
…
},
…
}
}