Corée du Sud : la couverture mobile

Ce que veulent dire les chiffres de Corée du Sud

Deux nombres comptent et un seul est celui que tout le monde cite. Le débit habituel, 104 Mbit/s, dit à quoi ressemble un bon moment.

Le dixième centile, 36 Mbit/s, c'est celui qu'il faut lire. C'est le débit du dixième le plus mauvais de la journée, quand l'antenne au-dessus de la gare est saturée et que tout le monde autour de vous est dessus. Un pays à médiane haute et à plancher bas, c'est un pays qui marche à merveille jusqu'au moment où vous en avez vraiment besoin.

Si le voyage dépend des appels vidéo ou du partage de connexion, organise toi en fonction du chiffre en heure chargée plutôt que du débit habituel.

Ce qui se passe en Corée du Sud quand le réseau est saturé

La congestion n'est pas une panne, c'est un mardi soir. La question est ce que votre eSIM peut y faire, et pour la plupart des eSIM de voyage la réponse est rien : un accord de gros par pays, un réseau, et aucune issue sauf acheter une deuxième eSIM chez quelqu'un d'autre, debout dans la rue.

Ici le trafic Orbislo passe par SKT et KT. Quand le réseau où vous êtes se dégrade, nous vous basculons sur un autre, en plein voyage, sans que vous demandiez, et nous vous le disons après plutôt que de vous interrompre sur le moment.

Les opérateurs mobiles en Corée du Sud

• 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.

Les anciens réseaux en Corée du Sud

• 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.

La 5G en Corée du Sud

• 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.

Le réseau en Corée du Sud : à savoir

• 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.