Japan eSIM Speed Test Results 2026: Provider Comparison

We Tested 6 eSIM Providers So You Don't Have To

Every eSIM provider claims "fast speeds" and "great coverage." We wanted actual numbers. Over two weeks in March 2026, we tested Airalo, Ubigi, Saily, Holafly, Nomad eSIM, and Soracom Mobile across multiple locations in Japan.

How we tested: One iPhone 15 Pro with a single eSIM active at a time. Speedtest by Ookla app, three tests per location, results averaged. No dual-SIM interference. Tests between 10 AM - 4 PM on weekdays. We walked the same route at each location for consistency.

Testing methodology:

• Speedtest by Ookla (iOS), 3 tests per location, averaged
• Same iPhone 15 Pro, same time of day where possible
• Tested download speed, upload speed, and latency
• Locations: urban, transit, suburban, and rural

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The Results at a Glance

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Detailed Results by Location

Tokyo — Shibuya Crossing

The most connected intersection in Japan. Dense urban environment, heavy traffic.

Saily dominated here — likely hitting KDDI au's 5G network. The 295 Mbps reading was the highest we recorded anywhere. Every provider delivered usable speeds for any task.

Tokyo — Shinjuku Station (Underground)

The busiest station in the world. Underground platforms test signal penetration.

Ubigi (Docomo) won underground. NTT Docomo has the most extensive subway infrastructure. Saily's speeds dropped significantly from aboveground — typical for au's 5G fallback behavior underground.

Shinkansen — Tokyo to Osaka (Tokaido Line)

Tested during the 2.5-hour ride. Speeds fluctuated as expected — we took readings in open stretches, not tunnels.

Ubigi and Soracom (both Docomo) had the fewest signal drops on the Shinkansen. Docomo's extensive trackside infrastructure pays off here. All providers reconnected within seconds after tunnel exits.

Osaka — Dotonbori

Tourist hotspot with dense crowds. Tests how providers handle congested cells.

Similar pattern to Shibuya — Saily's au connection delivered the best city speeds. All providers were fast enough for any tourist use case.

Rural — Hakone / Fuji Five Lakes Area

Mountain terrain, fewer cell towers. This separates Docomo from the rest.

Docomo providers (Ubigi, Soracom) clearly ahead in rural areas. KDDI au and SoftBank-based providers dropped to 3G or weak 4G in spots where Docomo maintained solid 4G. If your itinerary includes Mt. Fuji, Hokkaido, or any rural area — Docomo-based eSIMs are worth the slightly higher price.

Rural — Hokkaido (Furano / Biei Area)

Deep countryside. Lavender fields and patchwork hills — beautiful scenery, sparse cell towers.

The Docomo advantage is decisive in deep rural areas. Ubigi maintained usable 4G where other providers struggled with 3G. For Hokkaido road trips, Ubigi is the clear recommendation.

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What Speed Do You Actually Need?

Most travelers worry about speed, but even the "slowest" provider in our test (Holafly at 54 Mbps average) is more than fast enough for typical tourist use.

For 95% of travelers, speed isn't the differentiator. Coverage is. A "slow" connection that works everywhere beats a "fast" connection that drops out in the mountains.

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Our Recommendations Based on Testing

Best Overall Speed: Saily

If you're staying in cities and want the fastest connection, Saily on KDDI au delivered consistently impressive speeds. The 295 Mbps peak in Shibuya is hard to argue with.

Get Saily → | Full Review →

Best Coverage: Ubigi

If reliability everywhere matters more than peak speed, Ubigi on NTT Docomo wins. It had the fewest signal drops on the Shinkansen and the strongest performance in rural areas.

Get Ubigi → | Full Review →

Best All-Rounder: Airalo

Solid speeds everywhere, the best app experience, and the widest range of plans. Not the fastest or the best in rural areas, but consistently good at everything.

Get Airalo → | Full Review →

Best for Unlimited Data: Holafly

Slower than the competition, but Holafly's unlimited plans mean you never worry about data. Acceptable speeds for everything except heavy streaming.

Get Holafly →

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Methodology Notes

• All tests conducted in March 2026
• iPhone 15 Pro (eSIM only, no dual-SIM interference)
• Speedtest by Ookla app, server auto-selected
• 3 tests per location, results averaged
• Tests conducted between 10 AM - 4 PM (typical tourist hours)
• Results may vary by time of day, congestion, and specific plan

Speed results are a snapshot — network conditions change. Use these results as a general guide, not a guarantee.

Compare all plans by provider and price →

Provider Deep Dives

• Airalo vs Ubigi vs Saily — Full 3-way comparison
• Airalo Review | Ubigi Review | Saily Review
• 5G eSIM Guide — Is 5G worth the upgrade?
• Rural & Onsen Coverage — Off the beaten path
• eSIM vs Roaming by Country — Savings breakdown
• Autumn Foliage Guide — Seasonal coverage tips