South Korea's three mobile carriers earned more than 1 trillion won in combined revenue from artificial intelligence data center (AIDC) businesses in the first half of this year, driven by rising utilization as demand for AI computing surged. With data centers now scaling to the gigawatt (GW) level, the carriers are expected to manage their funding burdens by confirming customer demand in advance.
KT (030200.KS) reported second-quarter revenue of 6.68 trillion won ($4.9 billion) and operating profit of 648.3 billion won ($475 million) on a consolidated basis, the company said in a regulatory filing on the 12th. The figures were down 10.1% and 36.1%, respectively, from a year earlier. KT attributed the decline to a base effect, saying the year-earlier quarter had included one-time presale revenue and profit from the development of a site at its Gangbuk headquarters.
While overall earnings fell, the AI and cloud businesses that KT is growing as future engines — grouped under its AX segment — expanded at double-digit rates. Combined AX revenue from KT and KT Cloud reached 367.8 billion won in the second quarter, up 22.3% from a year earlier. KT Cloud posted second-quarter revenue of 265.4 billion won, up 19.8%. KT said the growth was led by newly operating data centers and an expanding data center design, build and operate (DBO) business.
The other two carriers likewise highlighted growth in their first-half AIDC businesses. SK Telecom's first-half AIDC revenue rose about 91% from a year earlier to 267.6 billion won, while LG Uplus grew about 30% to 238.5 billion won. Adding KT Cloud's first-half revenue of 515.5 billion won, the three carriers' combined AIDC-related revenue is estimated at 1.02 trillion won, up about 29% from a year earlier.
The revenue gains were underpinned by rising utilization. SK Telecom's data center utilization is believed to have approached 100% after its acquisition of the Pangyo IDC in the second half of last year. LG Uplus also saw its Pyeongchon Mega Center reach 98% utilization in its first year, while its Pyeongchon 2 Center had all 12 server rooms reserved at completion, maintaining strong demand.
The carriers are also stepping up long-term investment to meet that demand. KT said on the same day that it aims to secure 1 GW of AIDC capacity by 2031 and expand its submarine cable capacity by 90 Tbps to become an "Asia AX connectivity hub." SK Telecom has set up a dedicated AIDC subsidiary, SK Hyper, for large-scale development, while LG Uplus is expanding capacity centered on Paju.
AIDCs, however, carry higher power density than ordinary data centers and require high-performance power and cooling equipment, resulting in enormous upfront investment costs. That has made risk management a key task. Building infrastructure before securing enough customers leaves operators bearing the full financing costs after completion.
In response, the carriers are pairing their expansion plans with mechanisms to secure demand and spread the investment burden. Rather than building large data centers first and then seeking customers, they are scaling investment while confirming actual demand. KT CEO Park Yoon-young said at a first press conference after taking office that the company would invest about 5 trillion won over the next five years to expand AIDC capacity to 1 GW, but only on the premise of genuine demand. The approach means adding AIDC capacity in stages in line with customer acquisition, rather than building out unconfirmed capacity all at once, in order to reduce the burden of large upfront investment.
SK Telecom, when it unveiled a 15 GW AIDC construction plan in June, similarly outlined a phased approach: bringing 5 GW online in a first stage from 2029, then expanding to 15 GW based on market demand and business performance. It has also appointed Yoo Jae-ho, former head of SK Telecom's portfolio strategy office, as chief financial officer of SK Hyper, reinforcing its push to attract outside capital. The strategy is to spread the burden of large-scale AIDC investment using project financing (PF) and outside investment, led by Yoo, who previously oversaw new-business investment and M&A.
LG Uplus is lowering its investment risk through presales that secure customers before completion. The first building of its Paju AIDC, due for completion in June 2027, has already been fully sold while still under construction. Kim Jun-sup, an analyst at KB Securities, said the variable that determines a data center's performance is how long it takes to secure tenants after completion, adding that a high presale rate would improve the visibility of future revenue and profit.
