SoftBank slow internet in Japan: tests, evidence and complaints

If your SoftBank connection is slow or unreliable, start with these equipment checks. Then document a repeatable result and ask for a specific investigation.

Applies to: Paths checked in SoftBank’s setup pages for the 光BBユニット E-WMTA2.4 (top page version 1.8.8) and the ホームゲートウェイ（S） 10G E-WMTA1.0, which share the same menus. The older E-WMTA2.3 uses the same layout, but its Wi-Fi menu is called 無線LANの設定.Checked: 3 November 2026

When this helps

You use SoftBank in Japan.
Your connection is slower than expected, drops out or performs badly at certain times.

Check your 光BBユニット / ホームゲートウェイ（S）

These checks apply to 光BBユニット / ホームゲートウェイ（S）. Check the model before following its menus.

Open the セットアップメニュー and click 設定/接続情報 (Settings and connection info) for the current settings and connection details.
Click システムログ (System log) in the left menu for the unit’s event log.
On the 光BBユニット, PPPoEの設定 › 接続情報 (Connection info) shows each PPPoE session’s state.

Separate the service from your home Wi-Fi

For the exact settings and supported equipment, see the 光BBユニット / ホームゲートウェイ（S） guide.

Do not factory-reset the equipment as a first step. A reset can erase service settings and interrupt phone service.

Compare a wired connection to the router with Wi-Fi on the same device.
Repeat the same test server during the slowdown and at a quieter time.
Record download, upload, latency and whether another household device was using the connection.

How to complain to SoftBank

Use SoftBank’s official support to report the fault. Request a formal complaint reference if it remains unresolved.

Include the plan wording, dates, test conditions, previous references and the specific outcome you want. Ask for a written response.

Check the complaints procedure in your Japan service contract before escalating. Use the national regulator’s consumer guidance for your service.

Collect the evidence with Kilobat

On a Mac, Kilobat can record connection checks and produce a support report. Review the report and add your test conditions before sharing.

The basic report export is free. Kilobat Pro’s complaint wizard helps assemble your evidence, impact and requested resolution into a draft you review and send.

Measurements cover this Mac while monitoring ran. They cannot prove whole-home uptime, establish provider fault or replace a required official measurement procedure.

Sources

Checked on 3 November 2026.