SK Telecom


SK Telecom Co., Ltd., abbreviated as SKT, is a South Korean wireless telecommunications operator and former film distributor and is part of the SK Group, one of the country's largest chaebols. It leads the local market with 50.5 percent share as of 2008. SK Telecom is the largest wireless carrier in South Korea, with 23 million subscribers as of Q4 2023.
Since its creation in 1984, the company has evolved from a first generation analog cellular system, to second generation CDMA, then to the world's first third-generation synchronized IMT-2000 cellular system. SK Telecom also became the world's first carrier to commercialize HSDPA in May 2006. SK expanded into the landline market by acquiring second-rated fixed-line operator Hanaro Telecom in February 2008.
The company's online brands include Nate, a web portal, June, a mobile multimedia service, Moneta, an e-banking mobile app, Nate Drive, a telematics service, and Digital Home, an online interface to remote-control household appliances.
In 2004, SK Telecom launched Hanbyul, the world's first DMB satellite. TU Media, SK Telecom's digital media arm, handles DMB TV broadcasts.
In November 2015, SK Telecom announced signing a deal to acquire CJ HelloVision, the country's largest cable and Internet operator, with the view to merge it with its own cable unit, SK Broadband. The acquisition, which will make SK Broadband the second largest cable broadcaster following KT, is opposed by competitors, who charge that the merger will help SK unfairly dominate the market.

History

SK Telecom was established in March 1984 under the name Korea Mobile Telecommunications Services Corp., but was renamed Korea Mobile Telecommunications Corp. in May 1988. It was a subsidiary of the state monopoly phone company, Korea Telecom until KT sold it off in 1994. In June 1994 SK Group became Korea Mobile Telecommunications Corporation's largest shareholder. KMTC officially joined the SK Group in January 1997 and changed its name to SK Telecom in March of that year.
In October 2000, SK Telecom became the second operator in the world after NTT DoCoMo to launch a commercial 3G service using W-CDMA technology. In January 2002, this was followed up by launching the world's first CDMA2000 1xEV-DO network, offering greatly increased data transmission speeds to preexisting 2G networks.
In May 2005, SK Telecom divested 60 percent of SK Teletech stock to cellphone maker Pantech. SK remains the second largest shareholder by holding on to the rest of Teletech's stock.
In 2006, the well-known "SKY" brand of mobile devices became fully owned by Pantech as it finalized its takeover of SK Teletech.

1984–1993: early years

Founded on March 29, 1984, as Korea Mobile Telecommunications Services Corp., the state-owned carrier introduced pagers and car phones to the Korean market. May 1984 saw the launch of the car phone service. Korea Mobile changed its name to Korea Mobile Telecommunications Corp. in May 1988. In July, AMPS cellular network was initially launched in Seoul metropolitan area. By 1991 nationwide coverage was complete.
In April 1993, the South Korean government, through KMTC, adopted CDMA as the national cellular telephone system.

1994–1996: privatization and the CDMA standard

Through privatization, SK Group became Korea Mobile Telecommunications Corp.'s largest shareholder in June 1994.
In October 1994, Korea's first CDMA system was introduced to the public for the first time.
In January 1995, KMTC reached the one million subscriber mark. Korea Mobile Telecommunications became the third Korean firm to be listed on the NYSE exchange in June 1996. Later that year South Korea got its first commercial CDMA network. Operating in Seoul in October, it is considered one of the world's earliest commercial CDMA networks.

1997–2000: international expansion

SK Group completed its takeover of KMTC in January 1997, as it became the world's sixth carrier to attain ten million subscriptions. Around that time, it also began constructing the Northeast Asian CDMA belt encompassing China, Japan, Vietnam, and the rest of the Asian continent.
In March 1997, to reflect new changes, KMTC changed its name to SK Telecom, and in October, NetsGo, an online service, was launched.
In June 1998, SK Telink, the international call service division, started offering commercial overseas call service. In December 1998, SK Teletech launched its first handset. In April 1999, SK Telecom entered the Mongolian market by co-founding Skytel LLC with nearly 30 percent ownership stake.
TTL, a wireless plan targeting younger users, and nTOP, a cellular internet service were launched in July and October 1999, respectively.
In December 1999, SK Telecom surpassed ten million subscriber mark, the following month, it launched the world's first commercial CDMA2000 service. By the end of the year the carrier won a contract for asynchronous IMT-2000 facility.

2001–2007: cellular internet and market accrual

The new millennium ushered in an era of cross-platform online networks that saw efforts to integrate mobile services, as SK Telecom was exploring new value-creating models such as m-Commerce and satellite DMB Service.
In January 2002, an acquisition of Shinsegi Telecomm Inc. was completed. In the same month also, the company deployed world's first commercial synchronous IMT-2000 facility.
In March 2002, the carrier struck international roaming deals between countries using CDMA and GSM networks. An agreement was signed with Israel's Pele-Phone in April to sell proprietary software that will operate on the carrier's existing CDMA network and future 1x-CDMA network. In July, a MoU was signed with China Unicom to establish a joint venture. In November two mobile applications ‘June’ and ‘Moneta’ were launched. In July 2003, S-Fone, a commercial CDMA network became operative in Vietnam. In August 2003, June became the world's first 3G service to have one million subscribers.
In February 2004, SK won a contract for a joint venture with China Unicom, called UNISK.
In March 2004, Hanbyul, the world's first DMB satellite, was launched.
MelOn, an online music store was launched in November 2004. ‘1mm’ and ‘Loview,’ a digital photo frame service were launched in April and November 2005, respectively. By December, MelOn had four million subscribers.
SK Telecom started 2006 with record revenues of. In May the world's first commercial HSDPA handset was released. May also saw the carrier's entry into the U.S. wireless communication market with Helio. In June, SK Telecom signed a strategic partnership with China Unicom to purchase CB worth $1 billion in its subsidiary, China Unicom Hong Kong. In the same month SK deployed its WiBro internet network. In April 2007, a project to create TD-SCDMA, China's 3G wireless broadband equivalent was signed with the Chinese government. Around that time, S-Fone had two million subscribers in Vietnam.

2008–present: landline and new technologies

In November 2008, SK signed an agreement to buy a controlling stake of fixed-line phone company Hanaro Telecom for from a consortium led by AIG and Newbridge Capital. The new entity will be the second-largest telecom firm in terms of total assets and revenues next to KT Corp.
In 2013 SK Telecom was the world's first operator to offer a commercial LTE-Advanced network under the brand name bandLTE. This coincided with the release of the Samsung Galaxy S4 LTE-A model, which offered a step-up CPU and also LTE-Advanced capabilities. SK Telecom supported this handset at launch.
On July 6, 2013, it was reported that Apple was in talks with SK Telecom to release the iPhone 5s model on SK's LTE Advanced network.
On December 17, 2018, SK Telecom introduced the 'baro' roaming plan which offers unlimited use of international roaming voice calls. As of June 2019, 'baro' has drawn 2.2 million customers and 38 million total calls. It also won the 'Best Mobile Technology Breakthrough in Asia' award at the 2019 Asia Mobile Awards carried as section of MWC19 Shanghai.
In June 2019, SK Telecom announced the launching of the world's first 5G roaming service partnering with Swisscom.
In October 2020, SK Telecom formed a partnership with Uber Technologies, with a plan to break off mobility operation into a subsidiary called T Map Mobility.
In November 2021, SK Telecom spun off of a new company focusing on investments, semiconductors and ICT, SK Square.

Cybersecurity breach of 2021-2025

On April 18, 2025, SK Telecom informed authorities of a data leak, with full scope of the leak being unknown at the time. The information leaked in this incident includes the USIM authentication key, International Mobile Subscriber Identity, device identifier, and phone numbers.
In response to the breach, SK announced that all of its 23 million subscribers would be eligible for a free USIM card replacement starting from April 28, a week after the company publicly acknowledged the hack. Those who replaced their USIM earlier would be eligible for a refund. However, SK Telecom currently has only 1 million USIM cards available, leading to shortages and customer frustrations. Acting President Han Duck-soo directed related agencies to investigate SK Telecom's hacking countermeasures. SK said they are developing a way to format USIM cards without physically replacing them.
In July 2025, Korean Ministry of Science and ICT released a final report of the investigation. Base on the report, SK Telecom was compromised back in 2021 with attackers remaining active in SKT network undetected until 2025. According to the report, SK Telecom failed to properly manage sensitive accounts, encrypt sensitive data and did not respond adequately to previous security breaches, did not store critical security log information for sufficient time.
On August 28, 2025, the Personal Information Protection Commission issued a 134.8 billion won fine on SK Telecom over the data breach.