Verdict
I haven’t personally used this provider. Below is the public picture, sourced from Ubigi’s plans pages and terms.
Ubigi is one of the better global picks specifically because it carries NTT Docomo on its Japan plans — most international eSIM apps are SoftBank or KDDI au only. Buy if you’re spending real time outside major cities, or staying long enough that a monthly subscription beats a one-off plan. Skip if you want a single short-trip plan and don’t need Docomo coverage; cheaper SoftBank-only options exist.
What you actually get
Ubigi’s Japan plans connect to NTT Docomo and KDDI au — the two strongest networks for nationwide coverage. 5G is supported where those carriers have rolled it out (full sub-6 GHz in metro areas, 4G/LTE for most rural coverage). Ubigi operates as a full MVNO via its parent Transatel, which is part of NTT Group — a structural detail that helps explain the Docomo connection most global apps lack.
The lineup is unusually broad. One-off plans cover everything from a $3.50 / 1 GB / 3-day starter (the cheapest small plan in this comparison) up to a $65 / 30-day unlimited tier. Monthly subscription plans add 5 GB, 20 GB, and unlimited tiers billed in calendar months for long-stay travelers. There’s even an annual 60 GB / 12-month plan for residents and frequent visitors. Plans are data-only — no Japanese phone number, no SMS, no voice. No KYC.
Plans and pricing
Last verified May 2026.
One-off plans:
| Plan | Duration | Price (USD) | Network |
|---|---|---|---|
| 1 GB | 3 days | $3.50 | NTT Docomo / KDDI au |
| 1 GB | 30 days | $4.00 | NTT Docomo / KDDI au |
| 3 GB | 15 days | $7.50 | NTT Docomo / KDDI au |
| 5 GB | 15 days | $10.00 | NTT Docomo / KDDI au |
| 10 GB | 7 days | $14.00 | NTT Docomo / KDDI au |
| 10 GB | 30 days | $16.50 | NTT Docomo / KDDI au |
| 25 GB | 30 days | $32.00 | NTT Docomo / KDDI au |
| Unlimited | 7 days | $25.00 | NTT Docomo / KDDI au |
| Unlimited | 15 days | $39.00 | NTT Docomo / KDDI au |
| 50 GB | 30 days | $55.00 | NTT Docomo / KDDI au |
| Unlimited | 30 days | $65.00 | NTT Docomo / KDDI au |
Subscriptions:
| Plan | Billing | Price (USD) | Network |
|---|---|---|---|
| 5 GB / month | Monthly | $8 / month | NTT Docomo / KDDI au |
| 20 GB / month | Monthly | $19 / month | NTT Docomo / KDDI au |
| Unlimited / month | Monthly | $45 / month | NTT Docomo / KDDI au |
| 60 GB total (5 GB / month) | 12-month annual | $59 | NTT Docomo / KDDI au |
Ubigi’s $3.50 / 1 GB / 3-day plan is the cheapest short-trip plan with NTT Docomo coverage in this comparison. The monthly subscriptions price aggressively at the unlimited tier ($45/month vs $65 for one-off 30-day unlimited), useful for travelers staying multiple months. The annual 60 GB / 12-month plan is unusual — most providers don’t offer year-long plans at all.
Throttling and Fair Usage Policy
Ubigi’s fixed-plan tiers (1, 3, 5, 10, 25, 50 GB) do not throttle within the allowance — when you hit your limit, the plan stops or prompts a top-up.
The unlimited tiers apply a published Fair Usage Policy: 7-day country plans throttle to 2 Mbps after roughly 15–25 GB of high-speed use (Ubigi notes the threshold varies by country, with Japan-specific numbers not separately disclosed). 30-day regional plans throttle at 60 GB. The post-threshold 2 Mbps is meaningfully more generous than Airalo’s transparent 1 Mbps unlimited or Nomad’s 512 Kbps — at 2 Mbps you can still video call, stream music, and run translation apps with audio without obvious degradation.
For typical Japan travel use, even the lower 15 GB threshold is hard to hit in 7 days unless you’re heavily streaming or hotspotting. Ubigi’s unlimited tiers are among the cleaner unlimited propositions in this comparison: published thresholds, generous post-throttle speed, and no explicit hotspot/tethering restriction in the FUP documentation.
What public reviews and policy pages say
Public reviews of Ubigi for Japan consistently flag two things: the Docomo coverage advantage in rural areas, and the slightly clunkier app compared to consumer-first marketplaces like Airalo or Saily. The MVNO infrastructure shows up in connection-quality discussions — fewer “stuck on 3G” reports than reseller-based apps. The trade-off is fewer plan-size options at the small end.
How to buy and activate Ubigi
- Install the Ubigi app and create an account.
- Search “Japan” and pick a plan (15-day fixed, monthly subscription, or annual).
- Pay (cards, Apple/Google Pay).
- From the app’s plans tab, tap Install eSIM — your phone walks through the OS-level install.
- Set the new eSIM as your Cellular Data line; keep your home SIM active for calls and SMS.
- On arrival in Japan, toggle Data Roaming on for the Ubigi line. Ubigi may briefly attach to one carrier and then switch to the other based on signal strength — this is normal MVNO behavior.
- If data doesn’t connect, confirm the APN is set automatically, then toggle Airplane Mode off and on.
Who should pick Ubigi
- Rural Japan, Hokkaido, or Japanese Alps traveler — Docomo coverage is the differentiator and Ubigi is one of the cleanest ways to get it from a global app.
- Long-stay traveler or remote worker — monthly subscriptions price better than stacked short-trip plans.
- Anyone who’s been burned by reseller-app routing issues — full MVNO infrastructure is more predictable.
Who should skip Ubigi
- Single-week metro trip on a tight budget — Nomad or Saily on SoftBank is cheaper and the network gap doesn’t bite in Tokyo or Osaka.
- Existing Airalo or Saily user who’s already in another app’s ecosystem and doesn’t want to manage a separate Ubigi account.
- Travelers who’d rather not install another app — Ubigi requires its app for everything.
Frequently asked questions
Does Ubigi work in rural Japan and Hokkaido?
Yes. Ubigi is one of the few global eSIM apps that connects to NTT Docomo, the Japanese carrier with the widest rural footprint. Combined with KDDI au, that means strong coverage in Hokkaido, the Japanese Alps, and along the longer Shinkansen routes (Kanazawa, Sendai, Hokkaido).
What is Ubigi’s monthly subscription option?
Ubigi offers three monthly subscription tiers (5 GB at $8/month, 20 GB at $19/month, Unlimited at $45/month) and an annual 60 GB / 12-month plan at $59, all aimed at long-stay travelers, remote workers, and residents. The unlimited monthly is meaningfully cheaper than the one-off 30-day unlimited ($45 vs $65), so if you’ll be in Japan for a month or more on heavy data, the monthly is the better shape.
Does Ubigi require an app?
Yes. Ubigi requires its app for purchase and account management. The eSIM install itself uses your phone’s standard OS flow, but you need the app to top up, change plans, and view usage.
Is Ubigi a real MVNO or a reseller?
Ubigi operates as a full MVNO (mobile virtual network operator) rather than a reseller, which can mean cleaner connection quality and more predictable routing than some marketplace apps. It’s owned by Transatel, a long-running cellular MVNO.
Does Ubigi support 5G in Japan?
Yes. Ubigi supports 5G on its Japan plans where the underlying NTT Docomo and KDDI au networks have rolled it out, which in practice means full sub-6 GHz 5G in metro areas and 4G/LTE elsewhere.