Toward Commercialization: SoftBank Corp. Successfully Completes Japan’s First HAPS Trial Service

In late August 2026, residents near the Pacific coast of Shikoku, one of Japan's main islands west of Osaka, reported seeing a shiny, silver object, hovering high up in the sky. Some wondered whether it was a UFO.

What exactly was the object and what was it doing in the stratosphere? It turns out it was an LTA*¹ (Lighter than Air)-type High Altitude Platform Station (HAPS). Often described as "flying base stations," HAPS are designed to provide mobile connectivity from the stratosphere.

As reported earlier by SoftBank News, SoftBank Corp. (TOKYO: 9434) and its partner Sceye, Inc. have been preparing for a HAPS trial service in Japan. In August, they completed their mission, making them the first in Japan*² to successfully conduct stratospheric-based communications tests in Japan's airspace.

During the trial, which took place off Cape Muroto in Kochi Prefecture, SoftBank and Sceye confirmed the stable operation of voice calls and high-capacity data communications, such as video streaming and video calls. They also verified the operation of an emergency alert messaging system designed for use during large-scale disasters.

Pioneering new use cases for HAPS, SoftBank and Sceye also successfully validated HAPS-to-drone communications, and conducted the world's first technical verification of HAPS-enabled edge computing.*³

• *¹

  An LTA (Lighter Than Air)-type HAPS is a lighter-than-air platform that uses buoyancy to remain aloft.

• *²

  According to SoftBank research based on publicly available information as of August 23, 2026, this marks the first successful communications test in Japan between a HAPS and smartphones, as well as between a HAPS and drones.

• *³

  According to SoftBank research based on publicly available information as of August 23, 2026, this marks the world's first successful trial in which a mobile core network and web server were installed on a HAPS, enabling communications from smartphones to be processed entirely within the HAPS without being routed through a terrestrial network, with the results relayed back to smartphones.

A long-distance voyage in the stratosphere: Sceye's HAPS crosses the Pacific

Sceye's LTA-type HAPS used for this trial departed from New Mexico in the United States on August 9, 2026, Japan Standard Time (JST). It then flew more than 15,000 km across the Pacific Ocean in the stratosphere. Approximately 13 days after launch, it reached Japanese airspace at 7:11 a.m. JST on August 23.

The HAPS operated over an area around Muroto City, Kochi Prefecture, off Cape Muroto. Taking into account stratospheric weather conditions, including wind direction and wind speed, Sceye was able to maintain the platform's position for an extended period of time within a radius as small as 5 km. This achievement demonstrated both the platform's long-distance and long-duration flight capabilities, and its ability to remain over a target area of operation for an extended period in Japan.

After completing the trials in Japan, the HAPS began crossing the Pacific Ocean again to return to the United States. As of September 2, the HAPS flight is continuing.

HAPS-based communications performed with smartphones on the ground

Two-way communications tests were conducted between the HAPS in the stratosphere and smartphones on the ground in an area around Muroto City, Kochi Prefecture. For the tests, a 4G LTE-equivalent base station installed on Sceye's HAPS was connected to SoftBank's core network through a ground gateway.

The tests confirmed stable voice calls and text messaging, the use of apps, such as social media services, and high-capacity data communications, including video calls and video streaming. SoftBank and Sceye also successfully tested the operation of emergency alert messaging systems for earthquake early warnings and tsunami warnings, as well as voice calls to the 118 maritime emergency number in cooperation with the Japan Coast Guard.

In the data communications tests, the companies confirmed that communications performance equivalent to that of terrestrial networks could be achieved while reducing radio interference with terrestrial base stations.

Building a three-dimensional network: Communications between HAPS and drones successfully tested

In world first, HAPS-based edge computing technically verified

As the use of AI expands beyond information generation into areas such as Physical AI, lower-latency communications and data processing will become increasingly important. To explore the potential of edge computing in the stratosphere, a processing server was installed on the HAPS to conduct data processing directly on the platform.

The tests showed that the average round-trip response time for processing on the server onboard the HAPS was 68 milliseconds, reducing communications latency by more than 40% compared with processing in the cloud via the Internet. This marks the world's first successful test in which a mobile core network and a web server for processing were installed on a HAPS, enabling response processing to be performed entirely onboard the HAPS and the results to be relayed back to smartphones.

By combining the wide-area communications coverage provided by HAPS with edge computing technologies, SoftBank is aiming to enable new use cases that require both broad coverage and low latency, including applications in the field of Physical AI and real-time video analytics.

Advancing HAPS commercialization

SoftBank and Sceye will leverage the data and insights gained through these HAPS trial services, including those related to HAPS flight, operations, and communications, to further develop operational frameworks and improve communications quality, with the aim of commercializing HAPS services in Japan from 2027 onward.

Looking ahead to the 6G era, SoftBank also aims to realize a next-generation three-dimensional communications network by seamlessly integrating satellite, HAPS,and terrestrial communications networks to provide stable connectivity not only on the ground but also to aerial mobility systems, such as drones.

President & CEO Junichi Miyakawa said the successful trial "marks an important step toward the commercialization of HAPS."

"We will continue to integrate a wide range of technologies, including communications and AI, to develop HAPS into a new form of social infrastructure," he added.

For more details, please see this press release.

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(Posted on September 2, 2026)
by SoftBank News Editors