From October, Rakuten Mobile will continue using KDDI’s network in areas where it needs more time to build coverage, while roaming will be scaled back in areas where the telco already has sufficient coverage
In sum – what to know:
Roaming transition – Rakuten said roaming will continue from October where the telco still lacks coverage, while roaming will be scaled back where Rakuten already has coverage.
Rural talks – KDDI and Rakuten are still discussing whether roaming can continue for a limited period in certain sparsely populated rural areas.
Network investment – Rakuten plans JPY200 billion in 2026 base-station investment, with JPY65.5 billion spent by the end of June.
Japanese carrier Rakuten Mobile is finalizing a new arrangement with compatriot operator KDDI to continue roaming beyond the expiration of their current agreement at the end of September 2026, with the scope of roaming expected to be reduced as Rakuten Mobile expands its own network.
From October, Rakuten executives said that the telco will continue using KDDI’s network in areas where it needs more time to build coverage, while roaming will be scaled back in areas where Rakuten already has sufficient coverage.
During the telco’s recent earning call, Rakuten Group chief operating officer Kentaro Hyakuno said the company’s accelerated base-station rollout is not simply a response to the expiration of the roaming agreement with KDDI. The executive said that Rakuten had already planned to speed up network construction and is now proceeding at maximum pace, including bringing part of the construction process in-house to address Japan’s severe labor shortage. The strategy will allow Rakuten to progressively reduce its reliance on KDDI roaming as its own network footprint expands.
During the earnings call, Rakuten Group’s president and chief executive officer, Hiroshi Mikitani said negotiations with KDDI over roaming remain ongoing. He also said the companies’ relationship had been important to Rakuten Mobile since the start of its mobile business, with KDDI supporting Rakuten’s entry into the Japanese mobile market.
The two carriers signed the roaming agreement in 2018. KDDI has provided roaming access to its au network to support Rakuten Mobile, which entered the market as Japan’s fourth mobile carrier in 2020.
KDDI president Hirokazu Matsuda recently said that KDDI plans to end the current roaming support arrangement at the end of September, while discussions continue over a possible time-limited continuation in certain sparsely populated rural areas. The exact areas that could remain covered have not been disclosed.
Rakuten is also increasing investment in its own network. The company has said it plans to spend JPY200 billion ($1.3 billion) on Rakuten Mobile base-station buildout in 2026, compared with JPY62.9 billion in 2025. Rakuten had spent JPY65.5 billion of the 2026 budget by the end of June, with investment directed toward base stations using its 700MHz, 1.7GHz, 3.7GHz and 28GHz spectrum bands.
