Japan has fast, reliable mobile networks. Getting onto one is easy if you know which service fits your situation. The wrong choice costs you either money (overpaying for a major carrier when you only need MVNO speeds) or frustration (buying a tourist data SIM only to discover you cannot receive calls on it).
This guide splits the options by how long you are staying and what you actually need.
Note: mobile pricing, campaigns, and signup requirements change frequently. Treat the comparisons below as a 2026 planning guide and confirm the latest terms on each carrier's official site before you apply.
Two Categories: Short-Term Visitors vs Long-Term Residents
The Japanese mobile market divides naturally into two groups:
Short-term: Tourists, business travelers, and people in Japan for under three months. Priority is getting a SIM at the airport or convenience store without documentation. Data-only is often sufficient.
Long-term: People on working visas, student visas, or permanent residency who will be in Japan for months or years. You need voice capability, a reasonable monthly price, and a service that works reliably for daily life.
The requirements, prices, and recommended services differ substantially between these two groups.
Short-Term Options (Tourist and Data-Only SIMs)
IIJ Tourist SIM
IIJmio's tourist SIM is available at major airports and large electronics retailers like Yodobashi Camera and BIC Camera. It requires no contract-style resident registration — just payment and standard activation steps.
Options change over time, but the core appeal is the same: straightforward short-stay data access without the paperwork required for a long-term voice line. Speeds are capped at certain thresholds but remain functional for maps, messaging, and video. No voice calls are included.
For someone in Japan for two to four weeks, this is the simplest option. Pick it up at the airport kiosk, insert it, and you are connected.
Mobal Japan SIM
Mobal offers a SIM with a Japanese phone number and pay-per-minute call capability, which most tourist SIMs skip. If you need to make calls to local businesses, hotels, or landlords during a house-hunting trip, this matters.
Data rates are not competitive with IIJ for heavy users, but for occasional use and reliable call capability, Mobal fills a specific gap. It can also be ordered before you arrive in Japan and mailed to your home country.
Airport SIM Kiosks (Docomo, Softbank)
The major carriers operate kiosks at Narita T1, T2, Haneda, and other international airports. These SIMs are plug-and-play with no registration and offer various duration/data combinations. Prices are higher than IIJ for equivalent data, but the convenience of buying at the gate and having a familiar brand name is what you are paying for.
If you arrive late, need a SIM immediately, and the IIJ vending machine is sold out, the airport kiosks work fine.
Long-Term Resident Options (Voice + Data Contracts)
This is where the decision gets meaningful. You will live with whatever you choose for months, so understanding the trade-offs is worth the time.
Rakuten Mobile
Rakuten Mobile operates its own network (the fourth mobile network in Japan, built from 2020 onward) and prices aggressively to gain market share.
Rakuten's core plan structure is still one of the simplest in the market: pricing starts a little above ¥1,000 per month for light use and scales to a little above ¥3,000 for unlimited domestic data before optional discounts. Voice calls are free via the Rakuten Link app for most ordinary Japanese numbers. The plan includes a Japanese phone number and standard SMS.
The catch: Rakuten's own network coverage, while improved significantly since launch, still has gaps in rural areas and some indoor locations. Where Rakuten's network does not reach, it roams onto AU (KDDI) at no extra charge, but this roaming has limits. In Chiba and the broader Tokyo metro area, coverage is generally adequate for daily use.
For cost-conscious long-term residents who spend most of their time in urban areas, Rakuten Mobile is often the cheapest legitimate option. We recommend checking their coverage map specifically for your neighborhood before signing up.
IIJmio (MVNO on Docomo/AU)
IIJmio is an MVNO — a virtual operator that leases network capacity from Docomo and AU, then resells it at lower prices. The network is the same underlying infrastructure; the trade-off is potentially slower speeds during peak hours, since MVNO users are lower priority than the host carrier's direct subscribers.
In practice, IIJmio speeds are good for most everyday use in Chiba and Tokyo. Where you notice the difference is during rush hour in very congested areas — Shinjuku at 8 AM, for example. For remote workers, freelancers, and anyone not doing time-sensitive bandwidth-heavy work on mobile, IIJmio is reliable and reasonably priced.
As of March 2026, IIJmio's low-data voice plans still start below ¥1,000 per month, with mid-tier options staying comfortably below the major-carrier price level. Data can be rolled over, and the service is a solid choice for people who want stable MVNO performance without the coverage uncertainty of Rakuten Mobile.
Major Carriers: Docomo, Softbank, AU
The three major carriers offer the best network coverage, customer service infrastructure, and premium device support. They also charge materially more than Rakuten Mobile or the main MVNOs once taxes, device payments, and bundled options are included.
For most expats managing a budget, the premium is hard to justify. The main cases where the major carriers make sense: you travel frequently to rural areas where MVNO coverage thins out, your employer requires a specific carrier for device compatibility, or you want walk-in support in Japanese at a nearby store.
What You Need to Get a Contract SIM
A long-term contract SIM (voice + data, monthly plan) requires:
- Zairyu card: Mainstream postpaid voice plans generally require proof of mid- to long-term residence.
- Japanese address: Your registered address from your municipal registration.
- Credit card or bank account: For monthly billing. Some carriers accept debit cards; others require credit.
- Identity verification: Depending on the carrier, this may be handled online, by app, or in-store.
For the bank account requirement, see the guide to opening a Japanese bank account as a foreigner.
Data Speeds in Chiba vs Tokyo
Chiba sits on Docomo's and AU's strong suburban network infrastructure. Speeds in Makuhari, Chiba City, Funabashi, and Matsudo are comparable to central Tokyo for both major carriers and their MVNOs. You are unlikely to notice speed differences compared to living inside the Yamanote Line.
Rakuten Mobile's own network has solid coverage across Chiba City and the main JR corridors. The further you get from train lines in more rural parts of Chiba Prefecture (Choshi, Katsuura, Boso Peninsula), the more you rely on AU roaming.
eSIM Options
eSIM support is available from Rakuten Mobile, IIJmio, and several MVNO providers. If your phone supports eSIM (most phones released after 2019 do), you can activate a line digitally without waiting for a physical SIM to arrive in the mail.
Rakuten Mobile's eSIM setup is the most streamlined among long-term plans — it can be configured entirely through the app within minutes of plan approval. IIJmio also offers eSIM for compatible devices.
For the digital nomad context — using a Japanese SIM alongside a home-country eSIM for dual connectivity — see the digital nomad guide for Chiba and Tokyo.
For everything you need during your first weeks in Japan, including the order in which to handle SIM cards, bank accounts, and residence registration, the expat relocation guide for Chiba walks through the first-month administrative sequence.
Bottom Line
Short-term (under 3 months): Get an IIJ Tourist SIM at the airport for data, or Mobal if you need a Japanese phone number for calls.
Long-term (3 months or more): Rakuten Mobile is usually the cheapest full voice-and-data option if coverage in your specific area is adequate. IIJmio offers more predictable MVNO performance on established host networks and remains competitively priced as of 2026. Major carriers (Docomo, AU, SoftBank) are the most reliable but usually cost noticeably more without proportional benefit for most expats in urban Chiba and Tokyo.
Check Rakuten Mobile's coverage map for your neighborhood before committing. If the coverage is green in your daily routes, it is hard to beat the price.