Why do I have to choose 001, 002, or 00700 when calling from Korea?

South Korea kept the carrier-selection system that most countries abandoned around 2005. Each prefix routes the international call through a different carrier: 001 routes through KT, 002 through LG U+, and 00700 through SK Telink, which is SK Telecom's international subsidiary and not the same as your SK Telecom mobile plan. Rates and call quality vary by carrier. From a Korean mobile, hold 0 to type + and bypass the carrier-selection question entirely. The + shortcut routes through your mobile carrier's default international gateway.

Does the KT 001 Global Free plan actually save money?

It saves money if you cross 56 minutes of international calls per month. The plan costs 7,700 won monthly and includes 120 minutes to the US and other major destinations, with overage at 198 won per minute. Below 56 minutes you are paying for unused minutes, because the standard KT rate without the plan starts at 200 won per minute. KT advertises the 198 won rate as 86 percent lower than standard, which tells you the standard rate runs as high as 1,000 won per minute. For occasional callers, per-minute services without a monthly fee work out cheaper.

Is 1-800 toll-free from anywhere besides the US?

No, US 1-800 numbers are toll-free only inside the US. From Korea the call still rings through, but KT, SK Telecom, or LG U+ bills 200 to 1,000 won per minute regardless of the toll-free designation. Other countries have their own toll-free systems with different prefixes. The UK uses 0800, Australia uses 1800 inside Australia, Korea uses 080 domestically. None of these route as free internationally. Find the company's regular geographic +1 number, like +1 (267) 941-1000 for the IRS or +1 (212) 620-3418 for USCIS.

Are international calling cards still useful from Korea?

They can be, but the model is dated. You buy a physical or digital card, dial a Korean access number, enter a PIN, then dial the US destination. Per-minute rates can run as low as 50 won, but cards often have connection fees, weekly maintenance charges, and expiration dates that erode the apparent savings. Card quality and availability dropped after Korean carriers improved their own international rates around 2018. For most callers, browser-based VoIP services or the KT 001 Global Free plan are simpler than the access-number-and-PIN dance.

What time should I call US institutions from Seoul to catch them at opening?

Call at 8 PM KST during US standard time or 7 PM KST during US daylight saving, which lines up with the IRS international line opening at 6 AM ET. USCIS opens at 8 AM ET, which is 9 or 10 PM KST. Korea is 13 hours ahead of US Eastern during US DST and 14 hours ahead the rest of the year, because Korea does not observe daylight saving. Calling right at opening avoids the queue buildup. The West Coast 9 AM start lands at 1 or 2 AM KST, which is harder to schedule around.

How to Call US from South Korea (Cheapest Way 2026)

To call the US from South Korea, dial + on a mobile (hold 0 to type it), then 1, then the US area code, then the 7-digit number. From a landline, pick a carrier-selection prefix first — 001 for KT, 002 for LG U+, 00700 for SK Telink — then 1, the area code, the number.

What you pay depends on which carrier handles the call. KT's promoted 2025 rate runs 198 won a minute on a 7,700-won monthly plan. Without the plan, you can land anywhere from 200 to 1,000+ won a minute. Here's how to pay $0.04 a minute instead, plus the US numbers that work from Seoul.

How to Dial the US from South Korea

South Korea's exit code depends on which carrier you pick — 001 for KT, 002 for LG U+, 00700 for SK Telink — followed by 1, the US area code, and the 7-digit number.

Dial your carrier-selection prefix (or + from a mobile)
Dial 1 (US country code)
Dial the 3-digit area code
Dial the 7-digit phone number
Example: 001 1 267 941 1000 reaches the IRS international line

In 2026, Korea still asks you to pick which company handles your international call before you dial. Most countries dropped that system 20 years ago. Korea kept it. SK Telink (006, 00700) is SK Telecom's international subsidiary — not the same as your SK Telecom mobile plan.

From a Korean mobile, hold 0 to get + and dial straight through. That bypasses carrier-selection entirely.

How to Call the US from a Korean Cell Phone

From a Korean cell phone, hold 0 to type + and dial +1 plus the area code and number. It works on any Korean mobile regardless of carrier.

The dialing isn't the problem. The bill is. KT, SK Telecom, and LG U+ all charge between 200 and 1,000 won per minute to call the US — roughly $0.14 to $0.71. A 20-minute call to your US bank on a standard mobile rate runs 4,000 to 20,000 won, about $3 to $14.

Carrier (Prefix) | Rate to US | USD per Minute

KT (001) — standard | 200-1,000+ won/min | $0.14-$0.71

KT "001 Global Free" plan (Oct 2025) | 7,700 won/mo + 198 won/min overage | $5.50/mo + $0.14/min

SK Telecom / SK Telink (006, 00700) | 200-1,000 won/min | $0.14-$0.71

LG U+ (002) | 200-1,000 won/min | $0.14-$0.71

KT's October 2025 "001 Global Free" plan gives you 120 international minutes for 7,700 won a month and bills overage at 3.3 won per second. KT itself calls that rate "86% lower than the standard international rate" — which tells you what the standard looks like.

Here's how to pay $0.04 a minute instead.

Do US Toll-Free Numbers Work from South Korea?

US 1-800 numbers ring through from Korea, but they're not toll-free anymore. Your Korean carrier bills the call at full international rates.

This applies to every US toll-free prefix: 1-800, 1-888, 1-877, 1-866. The call connects, and your carrier bills 200-1,000 won a minute for the privilege of reaching a number marked "free" on the US end.

The fix: find the company's regular +1 (NXX) direct line. Banks, the IRS, USCIS, and the SSA all publish non-toll-free numbers for international callers. Use those.

Your Options for Calling the US from South Korea

You have four ways to call the US from Korea. Three of them cost too much.

Method | Cost | Setup | Best For

Korean carrier (KT/SKT/LGU+) | 200-1,000 won/min | None | Genuine emergencies

VoIP subscription | $10-30/mo + per-min | App, account, credit card | Daily callers

Calling card | Often cheap per-min | Buy card, dial access #, enter PIN | Patient price-hunters

WorldDialer (browser) | $0.04/min | None | Occasional callers

VoIP subscriptions assume you'll call internationally every week. Most expats and students don't. You sort out a Chase fraud alert from Seoul, and then you won't dial a US number for three months. Paying $15 a month for that is paying for the months you don't call.

WorldDialer runs in a browser. No app, no subscription required, no carrier-selection question. $0.04 a minute to US landlines, the same rate whether you're in Gangnam or Busan.

US Phone Numbers You'll Actually Need

These are the non-toll-free US numbers that work from Korea. Bookmark them. The 1-800 versions will just charge you international rates.

Institution | Number | Hours (US Eastern)

Chase Bank | +1 (713) 262-3300 | 24/7

Bank of America | +1 (315) 724-4022 | Mon-Fri 7 AM-10 PM, weekends 8 AM-5 PM

IRS International | +1 (267) 941-1000 | Mon-Fri 6 AM-11 PM

USCIS International | +1 (212) 620-3418 | Mon-Fri 8 AM-8 PM

SSA International | +1 (410) 965-0160 | Mon-Fri 9 AM-4 PM

The IRS and SSA publish these numbers on .gov sites — they're set up for calls from overseas. USCIS uses +1 (212) 620-3418 for international callers; the 800-375-5283 main line won't help you from Seoul. Calling US banks from abroad covers more institutions.

A 20-minute call to USCIS on a standard Korean mobile rate (500 won/min midpoint) runs about 10,000 won (~$7.15). On WorldDialer: $0.80. Same call. Same USCIS officer. Different bill.

When to Call the US from South Korea

Korea is 13-14 hours ahead of US Eastern Time. To reach a US business during their workday, call from Korea in the evening or late at night. KST is UTC+9 and doesn't shift for daylight saving — the US side moves twice a year, which is why the gap flips between 13 and 14 hours.

US East Coast 9 AM-5 PM = 10 PM-7 AM KST next day
IRS opens at 6 AM ET = 7 or 8 PM KST — call when they open
USCIS opens 8 AM ET = 9 or 10 PM KST
West Coast 9 AM-5 PM = 1 AM-10 AM KST next day

8 PM KST is the IRS-opens window. Call when the doors open, not after the hold queues build up. For expats managing US institutions, that one window does most of the work.

Call US Numbers from South Korea

You have the numbers. Here's the easiest way to dial them.

WorldDialer works from South Korea (and everywhere else). $0.04 a minute to US landlines. Browser-based, no carrier-selection prefix needed, no subscription required.

Next time you need to call home, we'll be here.

→ Try WorldDialer

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