If you search “best eSIM for Japan,” most articles blend two completely different audiences: a tourist staying five days, and a student, intern, or working-holiday visa holder staying six months to several years. Their needs — and the services they can actually sign up for — are not the same. Rakuten Mobile and povo, for instance, barely register outside Japan, because they’re never what a foreign visitor sees when they search their own country’s app store or a “Japan eSIM” query in English, French, or Spanish.
This guide splits the two groups apart, and for long-term stayers adds the practical details that most “top 3” lists skip: what documents you need, how contracts actually work, and step-by-step signup for each provider.
🧳 Short-Term / Tourist Trips: Top 3 by International Recognition
1. Airalo
Airalo is the default name international travelers reach for — it’s usually the first eSIM app people download before a trip, and for many travelers the logic runs in reverse of what you’d expect: they don’t pick Airalo because they’re going to Japan, they buy a Japan plan because they already have Airalo installed. In Japan, Airalo’s eSIM runs on the SoftBank network, which gives strong coverage in major cities and most of Honshu.
2. Ubigi
Ubigi is frequently recommended on English-language tech blogs and Reddit as one of the fastest, most reliable eSIMs in Japan. That reputation is backed by real infrastructure: Ubigi is operated by Transatel, which has been an NTT Group subsidiary since 2019, and its Japan plans route through the NTT Docomo network (with KDDI as a secondary network in some guides). Docomo has the broadest rural and mountain coverage of Japan’s three major carriers, which is why Ubigi tends to edge out competitors outside major cities, even if it isn’t always the cheapest per-gigabyte option.
3. Holafly
Holafly has strong brand recognition among travelers who specifically want unlimited data, driven by heavy influencer marketing on TikTok and Instagram. Among younger travelers in particular, “unlimited data” and “Holafly” are closely associated.
🏠 Mid-to-Long-Term Stays: Top 3 by International Recognition
This is the more important distinction. Someone who has just landed in Japan on a student, work, or working-holiday visa usually doesn’t yet have a Residence Card registered with an address, or a Japanese bank account — which rules out mainstream carriers like Rakuten Mobile, povo, NTT Docomo, au, or SoftBank’s own-brand plans, and MVNOs like IIJmio or b-mobile, all of which require an already-registered Residence Card. So the “top 3” for this group looks different: it’s the three companies built specifically around foreign residents who need to sign up before they have that paperwork sorted out.
1. Mobal
Mobal is consistently the first name that comes up in English-language forums and blogs for long-term expats, students, and English teachers, largely because it markets itself explicitly around one core promise: a real Japanese phone number (070/080/090, not a 050 internet number) without requiring a Residence Card. You can apply with just a passport. Mobal has a long operating history and English-first customer support, and it currently offers a roaming add-on that lets some users receive Japanese SMS verification codes even before landing in Japan — useful for registering on Japanese platforms in advance.
2. Sakura Mobile
Sakura Mobile is Mobal’s closest rival and shares the same core pitch: its Voice + Data SIM runs on the Docomo network and can be activated with just a passport — no Residence Card, no Japanese bank account, and no local credit card required (international cards are accepted). It markets heavily to students and interns through universities and study-abroad agencies, and it’s known for a wide range of data plan sizes (roughly 5GB–100GB/month) plus a student discount.
3. GTN Mobile
GTN Mobile is well known among foreign residents — especially from Asia — for its convenience-store cash payment option, which removes the need for a Japanese bank account or credit card at signup. Unlike Mobal and Sakura Mobile, GTN Mobile’s application does, in principle, ask for a Residence Card with your registered address; if you don’t have one yet, it accepts a passport plus an equivalent government-issued ID (such as a driver’s license) that shows your name and address instead. GTN also bundles life-support services (real estate, multilingual support in 13+ languages), which is why it’s especially well known among students and technical intern trainees who often find housing through the same company.
Data-only note: If you only need data (not a phone number), Ubigi — already covered above for short trips — also sells monthly and annual plans, making it a reasonable long-term data-only fallback.
What You Actually Need Before Signing Up
Requirements vary meaningfully by provider — this is the biggest correction worth making to the common assumption that a Residence Card is mandatory everywhere:
- Identification. Mobal and Sakura Mobile both accept a passport alone for their voice-capable SIM/eSIM — this is their main selling point over mainstream carriers. GTN Mobile prefers a Residence Card but will accept a passport plus a secondary government-issued ID showing your name and address if you don’t have one yet. Mainstream Japanese carriers and MVNOs (Docomo, au, SoftBank, Rakuten Mobile, IIJmio, b-mobile) generally do require a registered Residence Card, which is exactly why they’re not viable on day one.
- A Japan-reachable address (for physical SIMs). If you’re not picking up your SIM at the airport, you’ll need somewhere in Japan to receive it — a hotel, share house, or your registered address once you have one. eSIMs sidestep this by delivering activation details electronically or via an access code.
- A payment method. Mobal and Sakura Mobile accept international credit/debit cards, so a foreign-issued card works from day one. GTN Mobile additionally accepts cash payment at convenience stores, which is useful if you’d rather not use an overseas card for a recurring Japanese bill.
Step-by-Step Signup by Provider
Mobal — best if a Japanese number is your top priority
- Order online before you travel, paying by credit/debit card.
- Choose either home/hotel delivery (roughly 5–10 business days) or pickup at an airport counter or partner location in Japan — show your passport and order confirmation to collect.
- Insert the physical SIM or install the eSIM profile; the phone number is typically active on the spot, with English support available for setup.
Sakura Mobile — best for students and interns weighing plan-size options
- Choose a plan online (students can upload proof of enrollment for the discount).
- Complete identity verification (eKYC) with a passport photo — a Residence Card isn’t required for this plan.
- Receive your SIM and complete APN setup (usually automatic on iPhone; sometimes manual on Android), or activate your eSIM via the emailed profile.
GTN Mobile — best if you don’t have a credit card yet
- Apply online or at a partner GTN storefront.
- Verify identity with a Residence Card if you have one, or a passport plus a secondary ID if you don’t.
- If paying by convenience store, use the barcode/payment number GTN issues to pay in cash at a store like 7-Eleven, Lawson, or FamilyMart.
- Receive your SIM, complete setup, and start using service; GTN also offers an in-house EPOS credit card for residents who want to build a Japanese payment history.
Timing Strategy: Before vs. After Arrival
- Before arrival: Providers like Mobal and Sakura Mobile let you apply from overseas so you land with a working Japanese number already in hand — useful for airport pickup, initial paperwork, and apartment-hunting calls.
- After arrival, many stayers “bridge and switch”: start on Mobal, Sakura Mobile, or GTN Mobile to get a number immediately, then once a bank account and Residence Card are fully set up, port the number (MNP) to a cheaper mainstream MVNO like IIJmio or to Rakuten Mobile for lower long-term costs.
This two-stage approach — a foreigner-friendly bridge provider first, then a switch to a mainstream carrier once local paperwork is in order — is the pattern most long-term guides and expat communities describe as the practical default.
A note on what changed from typical “top 3” lists
The most common inaccuracy in this space is assuming all long-term SIM providers require a Residence Card. In practice, Mobal and Sakura Mobile were built specifically to work around that requirement using a passport alone, which is precisely why they dominate long-term recognition among people who’ve just landed. GTN Mobile is the one of the three that leans more heavily on the Residence Card, with a documented passport-based fallback.
