韓国の通信エリア

韓国 の数値が意味すること

重要な数値は2つあり、どの会社も引用するのはそのうち1つだけです。一般的な速度は104 Mbps。調子のいいときがどれくらいかを示す数字です。

読む価値があるのは10パーセンタイル、36 Mbpsのほうです。駅の上の基地局が混み合い、周りの全員が同じ電波につながっている、その日の下位1割のときの速度です。中央値が高くて下限が低い国は、本当に必要になるその瞬間まではみごとに動く国だということです。

ビデオ通話やテザリングが欠かせない旅なら、一般的な速度ではなく混雑時の数値を基準に計画してください。

韓国で回線が混んだときに起きること

混雑は故障ではなく、火曜の夜です。問題は、そのときeSIMに何ができるかで、たいていの旅行用eSIMの答えは「何もできない」です。国ごとに卸契約が1つ、ネットワークが1つ、路上に立ったまま他社のeSIMをもう1枚買う以外に逃げ道がありません。

ここではOrbisloの通信はSKT、KTを通ります。いま乗っているネットワークが劣化したら、旅行の途中でも、お客様が頼まなくても別の回線へ移します。そのときに邪魔をするのではなく、あとからお知らせします。

韓国の携帯キャリア

• SK Telecom: SK Telecom had 22,498,579 mobile handset lines at the end of June 2026, the most of the three network operators. Of those, 17,972,563 were on 5G and 134,413 were still on 3G.
• SK Telecom: Government investigators found that attackers took 25 kinds of USIM data from SK Telecom, 9.82 GB covering about 26.96 million subscriber identities, in a breach disclosed in April 2025. The malware had first been planted on its servers in 2021.
• KT: KT had 13,394,074 mobile handset lines at the end of June 2026, with 11,147,138 of them on 5G and 58,948 still on 3G.
• LG U+: LG U+ had 11,240,835 mobile handset lines at the end of June 2026, 9,548,153 of them on 5G. Unlike SK Telecom and KT, it has no 3G handset lines and no feature phone lines in the ministry's count.
• Resellers (MVNOs): Resellers that rent capacity on the three networks held 10,492,524 handset lines at the end of June 2026, about 18 percent of the national total of 57,626,012, and most of the country's 1,714,021 prepaid handset lines.

韓国の旧世代ネットワーク

• The communications regulator approved the closure of KT's 2G service on 23 November 2011, when about 159,000 customers, under 1 percent of KT's mobile users, were still on it. The 1.8 GHz band it used was rebuilt for LTE.
• SK Telecom's 2G shutdown was approved on 12 June 2020 after inspections found ageing equipment, missing spare parts and little redundancy. About 384,000 customers were still on 2G and were offered a free or subsidised handset or discounted plans to move.
• LG U+ began switching off 2G on 11 June 2021 and aimed to finish by the end of that month, after KT closed its 2G network in 2012 and SK Telecom in 2020. The old 011, 017 and 019 prefixes then merged into 010.
• No date has been set to close 3G. Ending a service needs ministry approval, and in December 2025 officials said only that some operators want to end 3G. The renewed spectrum licences let operators stop using their 3G frequencies or move them to LTE.
• Only 328,124 handset lines were still on 3G at the end of June 2026, well under 1 percent of the total, against 17,949,824 on 4G and 39,348,064 on 5G.

韓国の5G

• 5G signals first went live on 1 December 2018 for business customers using dongles. Smartphone 5G opened at 11 pm on 3 April 2019 on all three networks at once, starting with busy areas of Seoul, the capital region and some large cities.
• The June 2018 auction sold 280 MHz at 3.5 GHz for 2.996 trillion won: SK Telecom paid 1.2185 trillion won and KT 968 billion won for 100 MHz each, and LG U+ 809.5 billion won for 80 MHz. Each operator also took 800 MHz at 28 GHz.
• LG U+ was given a further 20 MHz at 3.40 to 3.42 GHz in July 2022 for 152.1 billion won, so all three operators now hold 100 MHz: LG U+ at 3.40 to 3.50 GHz, KT at 3.50 to 3.60 GHz and SK Telecom at 3.60 to 3.70 GHz, all running to 30 November 2028.
• The ministry cancelled the 28 GHz licences of KT and LG U+ for falling short of their build commitments, and SK Telecom's term was cut by six months. The only exception kept alive was 28 GHz use on subway lines the operators had promised to serve.
• Most Korean 5G still runs in non-standalone mode, leaning on LTE, and in December 2025 only KT ran standalone. The renewed 3G and LTE licences require every existing 5G site to connect to a standalone core by the end of 2026.

韓国のネットワークについて

• In rural areas the three operators split 5G construction and share the result. SK Telecom's shared network serves places such as Sejong, South Chungcheong and South Gyeongsang, KT's North Gyeongsang and Gangwon, and LG U+'s parts of the Jeolla provinces and Jeju, whichever operator your line belongs to.
• The 2025 government network test found poor 5G quality on 19 KTX and SRT high speed rail sections, mostly where operators share one network. Fixes are planned for the Gyeongbu and Honam lines during 2026 and for every high speed line by the end of 2027.
• Of 350 major facilities checked in 2025, 27 had a 5G signal too weak in at least a tenth of measurements. Twenty five of them were indoor sites, and 22 of those had no indoor 5G base station at all.
• On 25 October 2021 a wrong configuration command entered during a router replacement at KT's Busan office caused a routing error that took KT's internet service down nationwide for about 89 minutes. Investigators ruled out a denial of service attack.
• When one operator's radio network fails locally, disaster roaming moves its subscribers onto a rival network. After the 2021 KT outage the ministry planned to raise that capacity from about 2 million to about 3 million users, enough to cover a metropolitan city.
• In a declared communications crisis, the ministry's plan opens public and operator Wi-Fi, about 340,000 access points combined, to everyone under one network name, Public WiFi Emergency, as a fallback when your own operator's service fails.