Internet Options in Japan for Foreigners

The three real options

Almost every home internet decision in Japan comes down to three technologies. 光回線 (hikari kaisen, "fiber") is a physical fiber-optic line run into your unit — fastest and most stable, but it needs installation work (工事) and, in a rental, your landlord's sign-off. ホームルーター (home router, sometimes called plug-in fixed-wireless) is a device you plug into a power outlet that pulls a mobile signal from a nearby cell tower — no construction, no landlord paperwork, live the same day. 格安SIM (kakaku SIM, budget mobile) data plans round out the list as a data-only fallback: cheap, flexible, and fine as a bridge or backup, but not really built to be a household's only connection. This guide is the decision tree for picking between them — the detail pages linked throughout go deeper on each branch.

Step 1: what kind of building are you in?

Your building situation determines which options are even on the table, so start there rather than with price.

Detached house (戸建て)

If you're in a 戸建て, fiber is almost always viable, but every provider treats a house as new construction — a technician has to run a line to the building. Expect roughly 2–4 weeks from application to activation, and since you're presumably the leaseholder or owner, permission isn't usually the blocker; scheduling is.

Apartment with a visible 光コンセント (hikari konsento)

If your unit already has an optical outlet (光コンセント) on the wall — often labeled or in the same cluster as your other jacks — fiber is the easy case. In many buildings the fiber has already been run to the floor or the unit, so activation is a lighter "line-side" job rather than full construction, sometimes finished in under two weeks. This is the best-case path and worth confirming before you assume you need a home router.

Apartment where you can't confirm fiber

No visible outlet, an older building, or you just don't know — check before you commit to anything. Some buildings have fiber wiring already in the building but not yet in your unit; others have none at all and construction would mean drilling through shared walls, which management may refuse outright. See /blog/apartment-fiber-permission for how to ask your landlord or management company the right question, and what to do if the answer is no.

Short stay, or no landlord permission

If you're not staying long, can't get written permission for construction, or just need something working this week, a home router is the realistic path. It's the only one of the three that requires no construction (工事不要) and no landlord approval in most cases, since nothing is attached to the building.

Step 2: fiber vs. home router — the honest trade-off

Home routers plug straight into a wall socket, need zero construction, and are genuinely portable — take the same device to a new address and you're online again immediately. The catch is speed and consistency: advertised specs often cite multi-gigabit ceilings, but real-world throughput typically lands around 120–300 Mbps, latency runs roughly 2–4 times higher than a fiber line, and carriers throttle capacity during evening peak hours when everyone in the neighborhood is streaming at once. For browsing, video calls, and standard-definition or HD streaming, that's plenty. For competitive online gaming or moving large files constantly, it will frustrate you. Fiber is faster and far more consistent under load, but it costs you the 2–4 week wait and, in a rental, usually written landlord permission before anyone can drill. For a fuller side-by-side, see /blog/home-router-vs-fiber.

Step 3: don't trust the sticker price

Japanese internet pricing is built around campaigns, and the headline number on a provider's landing page is rarely what you pay over the life of the contract. Cashback amounts change month to month, most plans auto-renew on 2-year terms with a penalty if you cancel mid-cycle, and construction fees marketed as "実質無料" (effectively free) are often a monthly credit that claws back the remaining balance if you leave early. Before signing anything, work out the true cost over 24 months — monthly fee times 24, plus any construction charge, minus cashback actually received — rather than comparing initial prices. /blog/internet-contract-traps-japan walks through the specific clauses to watch for.

Rough price bands

Exact pricing varies by provider and campaign, so use these as planning ranges (list price, 税込 tax included) rather than quotes:

A 格安SIM data plan alone is rarely enough for a household — treat it as a bridge while you wait for fiber installation, or a backup if your main line goes down. Full plan comparisons are at /blog/sim-plans-japan-foreigners.

Step 4: sorting out the contract in English

Application forms, technician scheduling calls, and cancellation notices are often Japanese-only, which is the single biggest source of friction for foreign residents signing up for fiber. Some providers now offer English support lines or English-language application portals; others don't, and you'll be relying on translation apps or a Japanese-speaking friend. Check /blog/english-support-internet-providers before you commit if language support matters to you, and see /faq for quick answers to the questions that come up most — deposits, ID requirements, moving mid-contract, and what happens if you leave Japan before the term ends.

Putting it together

Work through the tree in order: confirm your building type and whether a 光コンセント already exists, decide whether you can wait 2–4 weeks and get landlord sign-off, and only then compare prices — using the real 24-month cost, not the campaign headline. Answer those three questions and the right option is usually obvious.