South Korea's high-speed internet speed has been ranked 22nd in the world, below Vietnam and Thailand, in foreign survey results, prompting debate. The government and the telecoms industry have moved to rebut the findings, citing limitations in the measurement method. They say it is difficult to judge network competitiveness based only on a simple speed ranking because internet product offerings and measurement environments differ by country.

The telecoms industry said on Oct. 15 that the Korea Telecommunications Operators Association (KTOA) questioned the reliability of the findings from the Speedtest Global Index by U.S. internet speed testing firm Ookla, saying they differ significantly from domestic high-speed internet quality assessments.

In Ookla's survey, South Korea's fixed high-speed internet download speed in August was 251.33 Mbps, ranking 22nd globally. Vietnam ranked 8th with 301.48 Mbps, and Thailand ranked 9th with 298.92 Mbps. South Korea slipped from 18th in August last year to 20th in March and 22nd in August.

Some have pointed to the results as evidence that domestic telecom operators did not invest enough in network upgrades. They said South Korea was relatively passive in improving existing infrastructure while Southeast Asian countries expanded fibre-optic-based networks.

Government and telecoms industry: Different measurement environments make country comparisons difficult

The Ministry of Science and ICT issued an explanatory note saying it is difficult to conclude that domestic internet quality has fallen behind based solely on Ookla's findings. It pointed out that Ookla does not disclose specific conditions such as the total number of measurements by country, the composition of internet products evaluated and the distribution of measured speeds. With subscription mixes differing by country, such as 100 Mbps, 500 Mbps and 1 Gbps plans, it said there are limits to comparing the results uniformly.

In a telecommunications service quality assessment conducted by the ministry last year, domestic high-speed internet download speeds were 91.91 Mbps for 100 Mbps-class service, 496.05 Mbps for 500 Mbps-class service and 987.70 Mbps for 1 Gbps-class service.

Speeds for 500 Mbps-class and 1 Gbps-class services improved from 494.47 Mbps and 983.25 Mbps a year earlier, respectively. The figures differ widely from the 251.33 Mbps presented by Ookla, but it is difficult to compare them directly because the two surveys differ in measurement targets and conditions.

KTOA raised the same issue. It said Ookla's survey is based on users voluntarily testing internet speeds, and results can vary depending on the device used, the time of measurement and the access environment. It also said it is difficult to directly compare network performance by country because the survey aggregates results measured under different conditions without distinguishing whether users are on fibre-optic cable or the speed cap of their subscription plans.

KTOA said it asked Ookla for detailed survey data in 2023 but did not receive specific materials. It plans to again request the measurement method and conditions and the provision of detailed data.

Fibre line share ranks second in OECD, rebutting claims of insufficient network investment

The government and the telecoms industry also cited Organisation for Economic Co-operation and Development statistics. As of 2025, fibre-cable-based lines accounted for 91.55 percent of South Korea's total fixed high-speed internet lines, ranking second among OECD members. That was well above the OECD average of 50.65 percent. It was higher than Spain at 91.06 percent, France at 82.17 percent and Japan at 79.22 percent.

The number of subscribers to high-speed internet at 100 Mbps or higher per 100 residents was also 46.23, ranking first in the OECD. The OECD average was 30.4.

KTOA said it is also untrue to conclude that the drop in South Korea's internet speed ranking is due to insufficient investment by telecom operators in network upgrades. It said speeds for high-speed internet products have continued to improve in domestic quality assessments since June 2023, when the installation of fibre cables in new buildings became mandatory.