Japan’s 5G Expansion: Key Insights on Speed, Availability, and Regional Gaps

Japan’s Competitive Mobile Market

Japan’s mobile industry is one of the most dynamic and competitive markets in the world, driven by four national operators—SoftBank, KDDI (au), Rakuten Mobile, and NTT DOCOMO. As 5G technology continues to expand, these telecom providers are adopting distinctive strategies to enhance speed, coverage, and overall user experience. Despite the saturation of the market, with a penetration rate of 157% and approximately 194 million cellular connections as of early 2025, the focus has shifted toward service quality and 5G availability. Data from Ookla’s Speedtest Intelligence (Q3 2025) highlights how these providers are differentiating themselves as they navigate the complexities of expanding 5G networks.

SoftBank takes the lead in overall median download speeds at 62.05 Mbps across all network types, slightly ahead of KDDI’s au network at 57.85 Mbps. However, Rakuten Mobile shines in the 5G category, delivering an impressive median 5G download speed of 128.39 Mbps. This competitive dynamic underscores how strategic network improvements, particularly in 5G deployment, are becoming critical for market leadership.

5G Availability: Disparities Between Urban and Rural Areas

While Japan has achieved remarkable progress in 5G population coverage—reaching 98.4% by the end of fiscal year 2024—availability data paints a more nuanced picture. 5G availability, which measures how often users with 5G-capable devices are connected to a 5G network, varies significantly across regions. NTT DOCOMO leads in this metric, with a 38.4% availability rate, over six percentage points higher than au. In contrast, SoftBank, despite its strong overall speeds, lags behind with 26.5% 5G availability, highlighting a typical trade-off between speed and coverage.

Regional disparities further underscore the urban-rural divide in Japan’s 5G rollout. Urban prefectures like Osaka and Tokyo see significantly higher access levels, with Osaka boasting 35.2% 5G availability and a remarkable median 5G download speed of 172 Mbps. Conversely, rural and mountainous prefectures such as Yamanashi struggle to achieve similar results, with only 9.1% 5G availability. These gaps reflect the challenges of deploying advanced telecommunications infrastructure in low-density areas while complying with government regulations that mandate coverage across all 47 prefectures.

Speed, Consistency, and Network Reliability

Ookla’s performance data reveals a strong correlation between higher 5G availability and improved network quality. Urban prefectures with dense populations and robust infrastructure have consistently reported faster speeds and narrower performance gaps. For example, Yamagata, despite a modest 5G availability of 13.9%, recorded the fastest median 5G download speed in the country at 181 Mbps. This anomaly suggests that lower congestion in areas with limited users can sometimes result in superior speeds for those connected.

Network reliability, as measured through 5G consistency scores, also reflects these dynamics. SoftBank, known for its high-speed performance, records excellent consistency in urban regions like Hokkaido and Tōhoku. Conversely, rural Kanto areas experience more variability in both speeds and reliability. Minimum speed analysis further highlights disparities; SoftBank delivers its highest low-end performance in Aomori at 49 Mbps, but significant dips occur in regions like Nagano, where speeds drop to as low as 4 Mbps.

Closing the Urban-Rural Divide in Japan’s 5G Landscape

Japan’s 5G ecosystem is a testament to the nation’s commitment to accelerating digital transformation. However, the persistent divide between urban and rural areas underscores the need for targeted investments in underserved regions. Expanding 5G infrastructure into remote areas will require significant capital and strategic planning to overcome topographical challenges and limited user density.

As Japan’s telecom providers continue to refine their approaches to network deployment, the ongoing disparities could affect the user experience and slow the potential of nationwide digital equity. Bridging the gap will not only enhance rural connectivity but will ensure that the rapid expansion of 5G technology benefits all citizens, regardless of location.