Base Stations in the Sky

SoftBank Corp. wants some of its base stations to float 20 kilometres above Japan. In June 2025 it said it would start pre-commercial services from high altitude platform stations (HAPS) in 2026, and in August 2026 a stratospheric airship built by its US partner Sceye flew all the way to Japan and connected ordinary smartphones to SoftBank’s network. This article explains what HAPS are, why Japan is a natural first market, and what the technology means for foreign partners.

What a HAPS actually is

A high altitude platform station is an uncrewed aircraft or airship that holds position in the stratosphere, around 20 km up, and carries radio equipment that works like a cell tower. It sits far above weather and commercial air traffic, but far closer to the ground than a satellite.

• Coverage — one platform can serve an area of up to around 100 km in radius, far more than a tower on the ground.
• Latency — the signal travels about 20 km rather than the 550 km of a low-earth-orbit satellite or 36,000 km of a geostationary one.
• Standard phones — HAPS can talk to unmodified handsets, so users do not need a special terminal or dish.
• Repositioning — unlike a satellite, a platform can be flown to where coverage is needed and brought back down for maintenance.

SoftBank’s two-track bet

SoftBank has worked on HAPS for years. Its former subsidiary HAPSMobile, now folded into SoftBank Corp., flew the solar-powered fixed-wing “Sunglider” into the stratosphere over New Mexico in 2020 and delivered LTE service from the aircraft. The company has also pushed for spectrum and regulation, working with other HAPS backers ahead of the ITU World Radiocommunication Conference in 2023, where frequency bands for HAPS-based mobile service were identified.

In 2025 SoftBank added a second, faster track. It made an equity investment in Sceye, a New Mexico company that builds lighter-than-air platforms, and on June 20, 2025 signed an agreement giving SoftBank exclusive rights to provide Sceye-based HAPS services in Japan. Airships can carry heavier payloads and stay aloft with less energy than a winged aircraft, which made an earlier start possible. SoftBank’s CEO said commercialisation had been targeted for 2029, but progress allowed pre-commercial operations in 2026.

Why Japan needs coverage from the sky

Disasters knock out towers

Earthquakes, tsunamis and typhoons regularly cut power and fibre to ground base stations. When the Noto Peninsula earthquake struck on January 1, 2024, mobile service failed across large parts of the peninsula and carriers had to bring in ship-based stations, drones and satellite backhaul. SoftBank says the first job for HAPS will be disaster preparedness: a platform can be flown over an affected area and restore service without waiting for roads and power lines to be repaired.

Mountains and islands

About 70 percent of Japan is mountainous, and the country has more than 14,000 islands. Building and maintaining towers in these places is expensive for very few users. A stratospheric platform can cover remote valleys, coastal waters and outlying islands in one footprint.

Drones and new users

The September 2026 demonstration also tested edge computing and drone communication. Ground networks are designed for people on the ground, while drones for logistics, inspection and agriculture need coverage in the air. HAPS can serve both.

The competition

SoftBank is not alone. KDDI already offers satellite-to-phone messaging through Starlink, and NTT, through its joint venture Space Compass with SKY Perfect JSAT, has invested in AALTO, the Airbus-backed maker of the Zephyr HAPS aircraft, with plans for services in Japan. The likely result is a layered network: ground towers for density, HAPS for regional coverage and resilience, and low-earth-orbit satellites for the widest reach.

Open questions

• Endurance — commercial service needs platforms that stay up for months, through winter nights with little solar power.
• Cost per platform — the business case depends on how many platforms are needed to cover Japan and how often they must be replaced.
• Rules — aviation and radio regulators must approve long-duration flights and spectrum use over populated areas.
• Timing — as of October 2026, SoftBank had demonstrated the system over Japan, but the start date and scope of the pre-commercial service had not been confirmed publicly.

What it means for foreign partners

• Component suppliers — lightweight solar cells, high-density batteries, antennas and flight control systems are all in demand, and Japan’s materials and electronics makers are natural partners.
• Disaster-response and public-sector buyers — governments in other earthquake- and typhoon-prone countries can watch Japan as a test market for HAPS in emergency communications.
• Drone and IoT companies — reliable coverage at altitude opens routes for delivery and inspection drones that ground networks cannot serve.
• Investors — SoftBank’s early exclusive rights in Japan make it the reference customer to follow. Read more on the group in our profiles of SoftBank Group and rival KDDI, and on Japan’s space start-ups in Synspective.

Conclusion

HAPS have been promised for decades, but in Japan they now have a carrier, a platform, spectrum and a clear first use case. If SoftBank’s pre-commercial service works as a disaster backup, it will give the world one of the first real tests of base stations in the stratosphere.