au (KDDI) Speed Test in Japan

Run a Speed Test

au (KDDI) delivers Fiber (FTTH) in Japan with typical measured speeds of 100–10000 Mbps. Run a free speed test to see what your line is actually producing — and how it compares to your plan.

About au (KDDI)

KDDI's au Hikari fiber service covers Japan's major metros with symmetric plans up to 10 Gbps. Consistent speeds; wired tests reliably hit 900+ Mbps on the gigabit plan. Strong alternative to NTT.

Technologies au (KDDI) uses

  • Fiber (FTTH)

au (KDDI) plans are symmetric, meaning upload and download speeds are roughly equal.

Typical au (KDDI) speeds

MetricExpectedWhat it means
Download range100–10000 MbpsReal-world wired-test range across plan tiers
Plan floor100 MbpsEntry-level advertised plan
Plan ceiling10000 MbpsTop-tier advertised plan
SymmetrySymmetricUpload matches download — ideal for video calls, cloud, and streaming

How to get an honest au (KDDI) test result

  • Test on a wired Ethernet connection — Wi-Fi alone can hide 10–30% of your real line speed
  • Run one test mid-morning and one between 7–10 PM local time — the gap exposes peak-hour congestion on the au (KDDI) segment
  • Watch ping and jitter, not just download — they determine whether calls, games, and cloud apps feel responsive
  • Run 3–5 tests back-to-back and use the minimum — that is the speed your real-time apps experience, not the marketing peak
  • If your wired test is consistently 20%+ below the plan, it is worth a support call to au (KDDI) — provisioning drift is real and they will usually refresh your modem remotely

Frequently Asked Questions

What speeds does au (KDDI) deliver in Japan?

au (KDDI) typically delivers 100–10000 Mbps in Japan across its Fiber (FTTH) plans. Run a wired Ethernet speed test to see what your specific line is producing right now.

Why is my au (KDDI) speed test slower than my plan?

The three most common causes are Wi-Fi (can hide 10–30% of real line speed), peak-hour congestion between 7–10 PM on shared segments, and outdated router or modem hardware. Run one test on Ethernet mid-morning and a second at 9 PM to see the gap.

Is au (KDDI) good for gaming and video calls?

au (KDDI) fiber plans deliver symmetric speeds with low jitter and are excellent for gaming and video calls. For competitive gaming, aim for ping under 30 ms and jitter under 5 ms on a wired connection.

How do I run an accurate au (KDDI) speed test?

Connect your device to the router via Ethernet cable, pause downloads and cloud sync, close streaming apps, and run 3–5 consecutive tests. Record the minimum result — that is the number that matches real-time usage, not the peak.

How we measure

The speed ranges and notes on this page combine publicly reported au (KDDI) plan information with wired Ethernet tests run through SpeedTestHQ across Japan. Figures are directional, not a guarantee — your actual results depend on your specific plan, address, router, and time of day. See our accuracy methodology.

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