A decade ago, South Korea had the world's fastest internet. It now ranks 22nd, trailing both Vietnam and Thailand.
South Korea's median fixed broadband download speed was 251.33 megabits per second in August, placing it 22nd globally, according to the Speedtest Global Index compiled by internet speed measurement firm Ookla, released on the 13th.
The country had ranked first in average connection speed in Akamai's State of the Internet report in 2017, meaning it slipped to 22nd in less than a decade.
Why Vietnam and Thailand Pulled Ahead
Southeast Asia drove the reversal. As recently as 2015, Vietnam's fixed internet speed was just one-sixth of South Korea's. Vietnam now records 301.48 Mbps, ranking eighth — 20% faster than South Korea and 14 places higher. Thailand, at 298.92 Mbps and ninth place, sits 13 places ahead.
Both countries have concentrated investment in recent years on replacing fiber-optic cable and expanding 5G infrastructure. Vietnam's fixed download speeds have climbed steeply through 2026. South Korea, by contrast, built world-leading high-speed networks in the early 2000s and has since been relatively slow to upgrade that infrastructure, analysts said.
The pattern holds at the city level. Seoul, at 238.69 Mbps and 34th place, lags Bangkok (321.90 Mbps, sixth), Ho Chi Minh City (298.38 Mbps, 14th) and Hanoi (251.94 Mbps, 30th). Singapore leads the world at 462.50 Mbps, 1.8 times faster than South Korea. The United Arab Emirates, Chile, Hong Kong, France and the U.S. all rank within the top 10, while China (24th) and Japan (26th) fall below South Korea.
Mobile is a different story. Over the same period, South Korea's mobile internet speed was 250.56 Mbps, sixth in the world. The raw speeds for fixed and mobile are similar, but the rankings diverge by 16 places. Only five countries — the UAE, Qatar, Kuwait, Germany and Brazil — outrank South Korea on mobile. On fixed broadband, 21 countries do.
The figures point to a gap between South Korea's early lead in 5G investment and its slower modernization of fixed-line infrastructure. One caveat: Ookla's methodology counts mobile Wi-Fi connections in its fixed-line measurements, making it difficult to read the rankings purely as a technology gap.