Can foreigners sign up for home internet in Japan?
Yes. Any resident on any visa can contract for home internet with a rental or ownership agreement and an account in your name. You will usually need your 在留カード (residence card) for ID verification, and many providers ask for a Japanese payment method.
What is 光回線 (hikari kaisen)?
Fiber-optic home internet — a physical fiber line run into your unit. It is the fastest and most stable option, but it needs installation work (工事) and, in a rental, often written landlord permission.
What is a ホームルーター (home router)?
A device you plug into a power outlet that connects over the mobile network. It needs no construction, works the same day, and is portable — but it has higher latency and can be throttled during evening congestion compared with fiber.
What is a 光コンセント (hikari konsento)?
An optical wall outlet where the building's fiber line meets your unit. If your unit already has one, fiber is usually a quick line-side activation; if there is none, you will likely need construction to run a line in.
What is 工事 (kouji) and how much does it cost?
The construction to run a fiber line to your unit. NTT's standard fee (revised December 2023) is about ¥22,000 for a house and ¥11,660–22,000 for an apartment. Where a 光コンセント already exists, a line-side activation is much cheaper, around ¥3,300.
What is 違約金 (iyakukin)?
A cancellation fee for leaving a fixed-term contract early. For contracts started on or after 2022-07-01, it is capped near one month's fee (about ¥3,000–5,700). Contracts from before that date are grandfathered and can be much higher (about ¥9,000–20,000+).
What is a 更新月 (koushin-tsuki)?
Your renewal month — the roughly 3-month window in which you can cancel a 2-year contract without a 違約金. Cancel outside it and you pay the fee and the contract auto-renews for another 2 years. Note your exact dates in your account portal (マイページ).
What does 実質無料 (jisshitsu muryou) construction mean?
“Effectively free.” The construction fee is split into installments offset by matching monthly discounts, so it nets to zero only if you stay the full term. Leave early and the remaining, un-offset balance is billed as a lump sum.
Is a “free” home router actually free?
The device's list price (about ¥33,000–95,000) is offset over roughly 48 months of bill credits. Keep it the full term and it nets to ¥0; cancel or switch early and you are billed the remaining device balance.
Should I trust big キャッシュバック (cashback) offers?
Treat them as uncertain, not guaranteed money. Cashback often arrives 6–12 months later, must be actively claimed via an email sent to a provider-issued address you rarely check, and is forfeited if you miss the claim window. Compare providers on true cost without it.
Home router or fiber — which is better for me?
For streaming, video calls, browsing, and casual gaming, a home router is genuinely fine and far easier to set up. For competitive gaming, large uploads, or a household running many heavy devices, fiber's lower latency is worth the install. If you cannot install fiber, a home router is the realistic choice.
What is VDSL, and why might my apartment be slow?
Some buildings distribute fiber to units over old copper phone lines (VDSL方式), which caps real-world speed around 100 Mbps even on a “1 Gbps” plan. The faster setup is 光配線方式 (dedicated fiber to each unit). Ask which one your building uses.
How much should a budget SIM (格安SIM) cost?
Roughly ¥850–1,100/month for a light ~3GB tier, or ¥1,600–3,300/month for a ~20GB tier (tax-included, 2026). If you are paying much more than that on a big-carrier plan for similar data, you are overpaying.
What is MNP, and how do I keep my phone number?
MNP (Mobile Number Portability) lets you switch carriers while keeping your number. Either get an MNP予約番号 from your current carrier and use it to sign up with the new one, or use MNPワンストップ (since May 2023) to do the whole switch through the new carrier's site. It is usually free.
Are there internet or mobile providers with English support?
Yes. Specialists such as Sakura Mobile, Mobal, and GTN Mobile offer English contracts and support and often skip the Japanese credit-card or guarantor requirement — at roughly 2–4x the price of a bare-bones 格安SIM. Most of the cheapest Japanese plans are Japanese-only.
Is the calculator's cost my exact bill?
No — it is an estimate using list / tax-included (税込) base fees plus the standard construction fee spread over 24 months, and it deliberately excludes campaign cashback and monthly-varying extras. Confirm exact terms with the provider before signing.