International dialing codes are uniquely assigned telephone number prefixes for each country, used to distinguish between calling and receiving countries in international calls. For example, South Korea's country code is +82, the United States is +1, Japan is +81, and China is +86. When making international calls, you first dial an international access code (in Korea: 001, 002, 00700, etc.) before the country code, or use the + symbol on mobile phones. International dialing codes are managed by the International Telecommunication Union (ITU) and range from 1 to 3 digits according to the E.164 standard. Some countries share a country code like the US and Canada, while others like European countries each have their own unique numbers. Currently, over 200 countries and territories worldwide use unique country codes. When making actual international calls, it's important to check international calling plans from different carriers. In Korea, services like KT's 00700, SK Telecom's 00700, and LG U+'s 00796 offer various international calling services with different rates and call quality. Recently, internet telephony (VoIP) and messenger app international calls have become popular due to their low cost and convenience.
Major Asian countries' international codes include South Korea +82, Japan +81, China +86, Taiwan +886, Thailand +66, Singapore +65, Vietnam +84, Philippines +63, and Indonesia +62. Be careful with China and Taiwan as their numbers are similar. When calling Japan, you must remove the leading 0 from area codes. For example, to call Tokyo (03), you should dial +81-3-xxxx-xxxx. Major European countries use UK +44, France +33, Germany +49, Italy +39, Spain +34, Netherlands +31, Switzerland +41, and Russia +7. Russia shares its country code with Kazakhstan, so they must be distinguished by area codes. European countries benefit from EU roaming regulations allowing phone use within the EU without additional charges, but international calling fees apply when calling from outside the EU. In the Americas, the United States and Canada share +1, while Mexico uses +52, Brazil +55, and Argentina +54. When calling the US or Canada, enter a 3-digit area code followed by a 7-digit phone number after +1. For example, to call New York's 212 area, dial +1-212-xxx-xxxx. The US uses different area codes for each of its 50 states, so caution is needed.
The most effective way to save on international calling costs is using internet telephony (VoIP) services. Voice calling features in messenger apps like KakaoTalk, Line, WhatsApp, and Telegram use Wi-Fi or data, allowing nearly free international calls. However, both parties must use the same app, and call quality may vary depending on internet connection. If you need to make international calls from a regular phone, compare international calling plans from different carriers. KT's World Call offers discounts on per-minute base rates, SK Telecom's T world direct provides discounted rates for major countries, and LG U+ offers products combined with internet telephony. Rate differences vary significantly by carrier and frequently called countries, so it's important to choose a plan that matches your calling patterns. Prepaid international calling cards and app-based services are also good alternatives. International calling apps like Boston, Ningio, and Conet offer rates 50-80% cheaper than regular phone charges. Prepaid cards can be purchased at convenience stores or online, and you should check the validity period and available countries before buying. For long-term stays or studying abroad, purchasing a local SIM card is the most economical option.
To use international calls efficiently while traveling abroad, preparation before departure is necessary. First, check if your phone supports roaming in the destination country and learn about your carrier's international roaming plans. SK Telecom, KT, and LG U+ all offer daily roaming plans with maximum daily charges to prevent unexpectedly high bills. Purchasing a local SIM card is also a good option. They are easily available at airports or convenience stores, and prepaid tourist SIMs offer affordable data and calling. Recently, eSIM services have increased, allowing use of local plans without physical SIM card replacement. Using eSIM apps like Airalo or Holafly, you can set up service before traveling for convenience. For business purposes, reliability and call quality are important. Cloud phone services like Zoom Phone, Google Voice, and Microsoft Teams provide stable quality calls from anywhere in the world, with features needed for business such as recording, auto-response, and call forwarding. If your company frequently handles international business, contracting corporate international calling plans can save costs in the long run.
The simplest way to make international calls on smartphones is using the + symbol. On the phone number entry screen, long-press 0 to display the + symbol, then enter the country code and phone number. For example, to call New York in the US, enter +1-212-xxx-xxxx. The + symbol automatically selects the international access code, making it very convenient. Both Android and iPhone allow saving phone numbers in international format in contacts. When saving contacts in +country code format, you can call the same contact from any country, which is convenient. If you frequently make international calls, it's recommended to standardize all contacts in international format. Precautions for international calling include: First, consider time zones. Korea and the US East Coast have a 14-hour difference, Europe 7-8 hours, so call at appropriate times. Second, international calling charges while roaming can be very expensive, so it's better to use Wi-Fi or VoIP services. Third, some countries require adding or removing a 0 after the country code, so check each country's phone system.
Understanding international calling requires knowing several concepts beyond country codes. First, ISO country codes are standards that represent countries with 2-letter (KR, US) or 3-letter (KOR, USA) characters, used mainly in internet domains or international documents rather than phone numbers. For example, Korea's internet domain .kr follows the ISO 3166-1 alpha-2 code. Area codes are numbers that distinguish regions within countries. In the US, 212 is New York, 213 is Los Angeles; in Korea, 02 is Seoul, 031 is Gyeonggi Province. When making international calls, you enter the area code after the country code, and in many countries you must remove the leading 0 from area codes. For example, London's area code is 020, but when calling internationally, you dial +44-20-xxxx-xxxx. Emergency phone numbers also vary by country. Korea uses 112 (police) and 119 (fire/ambulance), but the US uses 911, Europe uses 112, and Japan uses 110 (police) and 119 (fire). When traveling abroad, it's safe to know the emergency numbers of your destination country in advance. In most countries, you can make emergency calls even from a locked phone screen, and they connect to local networks even without a roaming SIM.
