When you move into a Japanese mansion (マンション, the Japanese term for a mid- or high-rise steel-reinforced-concrete apartment building — not a large luxury house as the English word suggests) and go to choose an internet plan, the first thing to check is not the monthly price. It is two things: the building's internal wiring method and its internet-readiness status. Together, these two factors all but decide the maximum speed you can achieve and whether construction work is required, so comparing plans is best left until afterward. This article walks through the difference between an apartment (MDU) plan and a detached-house plan, the speed gaps caused by the in-building wiring method, how to verify a unit's readiness status, and rough speed targets for remote work, streaming, and gaming — everything you need to choose with confidence. For overseas readers used to simply picking a broadband provider by street address, this building-first logic is one of the most distinctive features of the Japanese rental market.
Key points of this article
- For a Japanese apartment, the usable speed and whether construction is needed are largely decided by the building's "wiring method" and "readiness status," not by the plan you pick.
- If the in-building wiring is the optical (fiber) method, the standard maximum is 1 Gbps; the VDSL method and the LAN method top out at 100 Mbps (real-world speeds vary with the environment).
- "Internet fully-equipped" means you just plug in; "internet-ready" means a drop-in installation is required; "not installed" means you obtain the owner's permission and contract on your own.
- For remote-work-centered use, aim for roughly 30 Mbps of effective speed; for 4K video or multi-person households, target several tens of Mbps or more for comfort.
- If you are unhappy with the speed, upgrading your Wi-Fi router or changing the wiring method can sometimes improve it.
Choosing an apartment internet line comes down to "wiring method" and "readiness status"
To put the conclusion first: in a Japanese apartment, a large part of the decision has already been made by the building's equipment. Unlike a detached house — where you can freely choose a provider and chase raw speed — an apartment does not always give you that freedom. This is a sharp contrast with many Western markets, where a tenant in a multi-unit building can often order service from any carrier that covers the address. In Japan, the first things to confirm are not price or brand recognition, but two points: which wiring is installed in the building, and what readiness status your specific unit has.
In practice, when we advise clients on rental properties, more and more people now ask "is the internet fast?" at the viewing stage. According to Japan's White Paper on Information and Communications, fiber-optic coverage of Japanese households has reached about 99.8% (99.84% as of the end of March 2023) (source: 総務省 情報通信白書 令和6年版 (Ministry of Internal Affairs and Communications, MIC, White Paper on Information and Communications 2024)). In other words, whether fiber "reaches the building" is rarely the question anymore; comfort now hinges on how the signal is distributed to each unit inside the building. This is exactly where Japan's multi-dwelling-unit (MDU) wiring differs from a single detached line, and it is why pinning down the wiring method and readiness status first is the surest first step toward a line you will not regret.
What is the difference between an apartment plan and a detached-house plan?
The wiring architecture, and the freedom to choose a provider, are fundamentally different. An apartment (MDU) plan brings a single line into the building's common area — the kyōyō-bu (共用部, the shared parts of the building such as the entrance hall, riser shafts, and equipment rooms, which no individual tenant owns) — and distributes it from there to each unit. A detached-house plan runs the line directly from the utility pole into your own home, so in principle you monopolize the connection. The table below organizes the differences.
| Comparison item | Apartment (MDU) plan | Detached-house plan |
|---|---|---|
| Wiring architecture | Drawn into the common area, then distributed to each unit | Drawn directly from the utility pole into your own unit |
| Freedom to choose a provider | Tends to be limited to the providers already installed in the building | Free choice within the service area |
| Monthly-cost tendency | Tends to be cheaper because it is shared among residents | Tends to be pricier because it is a standalone contract |
| Speed stability | Can drop at night when many residents in the same building are online | You can monopolize the line and are less affected by congestion |
| Construction until activation | No work needed if "fully-equipped"; "ready" requires a drop-in installation into the unit | Requires an outdoor drop-in installation (owner permission assumed) |
| Speed ceiling | Governed by the building's in-building wiring method (explained in the next section) | Depending on the plan, you can even choose 1 Gbps to 10 Gbps |
The key point is that an apartment plan's "speed" and "cost" tend to be capped by the building's equipment. If you value remote work or gaming when choosing a rental, confirming the wiring method in the next section — at the same priority as floor plan and rent — will leave you with far fewer regrets. For international investors positioning a rental unit, this is also a signal worth reading: a building whose wiring caps speed at 100 Mbps may struggle to attract remote-working professional tenants, while a fiber-wired unit can be marketed on connection quality.
The in-building wiring method changes the maximum speed | Comparing optical, VDSL, and LAN wiring
Even for the same "fiber-compatible" building, the maximum speed varies greatly depending on the wiring method from the common area to each unit. The line may be fiber up to the common area, but whether the final stretch is a telephone wire or a fiber cable can make a tenfold difference in the ceiling — and that is far from rare. Here we compare the three representative methods. Overseas readers can think of this as the same problem as fiber-to-the-building versus fiber-to-the-home, but in Japan it is formalized into three named categories that appear directly in property listings.
| Wiring method | Wiring from common area to each unit | Standard maximum speed | Characteristics / how to identify |
|---|---|---|---|
| Optical (fiber) method — hikari haisen hōshiki (光配線方式) | Fiber-optic cable | Up to 1 Gbps (up to 10 Gbps on some plans) | The fastest. The telltale sign is an "optical outlet" (光コンセント / 光ローゼット, a fiber wall socket) on the wall |
| VDSL method — VDSL hōshiki (VDSL方式) | Telephone-line (metal/copper) cable | Up to 100 Mbps both up and down | You plug a telephone cord (modular cable) into a modem. Common in older buildings |
| LAN method — LAN haisen hōshiki (LAN配線方式) | LAN (Ethernet) cable | Up to 100 Mbps (some properties reach 1 Gbps depending on equipment) | There is a LAN port on the wall; you plug an Ethernet cable in directly |
The speeds above are strictly the standard maximums; the effective speed changes with the building's equipment, the time of day, and your in-home devices. The VDSL method in particular uses telephone wiring, so it is susceptible to distance and electrical noise, and measured speeds can fall further still. As numerical backing, the optical method reaches up to 1 Gbps (up to 10 Gbps with services such as FLET'S Hikari Cross / フレッツ 光クロス), while the VDSL and LAN methods carry a 100 Mbps standard difference (reference: NTT東日本 公式お知らせ (NTT East, official notice)). This three-way split has no exact equivalent in most Western listings, where broadband is usually advertised only as a headline speed tier rather than by the physical medium reaching the unit.
Steps to identify the wiring method in your own unit
You can confirm the wiring method in the following order. Even before signing a contract, you can ask the management company or the real-estate agency and they will tell you.
- Look at the wall socket. If there is an optical outlet, it is the optical method; if a modem is connected to a modular (telephone) jack, it is likely the VDSL method; if there is a LAN port, it is likely the LAN method.
- Check the "equipment" (setsubi, 設備) field of the property brochure or listing sheet for the line type (optical, VDSL, etc.).
- If it is unclear, ask the management company or owner, or the official contact desk of the installed provider, using the building name.
Note that NTT East ended new applications for the VDSL and LAN methods (FLET'S Hikari Next Mansion Type / フレッツ光ネクスト マンションタイプ) in 2024 and is promoting a switch to the faster optical method — a process known as hikari haisen-ka (光配線化, fiber-wiring conversion) (source: NTT東日本 公式お知らせ (NTT East, official notice)). Even a building currently on the VDSL method may be converted to optical wiring in the future, so if it matters to you, it is worth confirming the installation plan with the management company. Unlike most Western markets, where such infrastructure upgrades are handled quietly between the carrier and the building owner, in Japan the building owner's decision directly determines what the tenant can order. Owners considering bringing fiber into a building may also wish to read how to install a fiber-optic line in an apartment building.
How do you check an apartment's internet-readiness status?
Internet-readiness status falls into three categories — "fully-equipped," "ready," and "not installed" — and the required procedures and costs change with each. Listing sheets note this as "internet fully-equipped" (インターネット完備) or "internet-ready" (インターネット対応), so the quickest route is to confirm this category on the property materials first. These labels are a Japanese listing convention with no direct Western counterpart, and misreading them is a common cause of post-move-in surprises for newcomers to Japan.
| Category | Equipment status | What you need at move-in | Rough cost |
|---|---|---|---|
| Internet fully-equipped (インターネット完備) | The line is already activated all the way to each unit | Usable immediately by plugging in a LAN cable, etc. Many such properties require no individual contract | Free, or included in the rent or common-service fee |
| Internet-ready (インターネット対応) | Fiber is drawn into the common area only | Choose and contract a provider, then have a drop-in installation done into the unit | The plan's monthly fee + installation cost (free campaigns exist) |
| Internet not installed (インターネット未導入) | No line equipment | Obtain the owner's permission and contract/install yourself. If not allowed, consider a mobile line | Monthly fee + installation cost, or the monthly fee of a fixed (home) router |
Steps to confirm readiness status and avoid trouble after moving in
- Confirm the category on the listing sheet and property materials. Look for the "fully-equipped" or "ready" label and, if possible, the line type (wiring method) too.
- If it is fully-equipped, confirm the speed and the line provider. Because the shared equipment is split among all units, the effective speed at night can be lower than expected. If possible, ask for measured values or residents' feedback.
- If it is ready, confirm which providers you can contract yourself and the installation schedule. Right after moving season, construction slots are crowded and activation can take several weeks, so arrange it early.
- If it is not installed, confirm with the owner whether contracting and construction are permitted. Any work that drills a hole in the wall requires permission. If permission is not granted, a construction-free home router or a pocket Wi-Fi device becomes an option.
"Fully-equipped" is attractive for its convenience, but it is worth understanding that you cannot choose the line provider or the speed yourself. If speed is your top priority, a "ready" property where you can select your own provider is sometimes a better fit than a "fully-equipped" one. When you want to improve the felt Wi-Fi performance in a property whose line you cannot choose, the in-home improvements introduced in our complete guide to apartment Wi-Fi can help. For international readers, this trade-off — convenience of a bundled line versus control over speed — mirrors the choice between a landlord-provided "amenity" internet and a tenant-arranged private line seen in some Western multi-family buildings.
How much speed do you need by use case? Targets for remote work, video, and gaming
The speed you need varies greatly by use case, and most everyday use is fine with an effective speed of several tens of Mbps. It is tempting to think "faster is always better," but a plan that is excessive for your use is simply a waste of money. The table organizes rough targets for the main use cases, based on figures published by each provider.
| Use case | Target effective speed | Notes |
|---|---|---|
| Web browsing, email, social media | Around 10 Mbps down | Everyday use is fine with a few Mbps to 10 Mbps |
| Video meetings (remote work) | 10 Mbps or more consistently (around 20 Mbps for hosting) | For Zoom, a one-on-one HD call needs about 1.2 Mbps up/down; a group HD call needs about 2.6 Mbps up and 1.8 Mbps down |
| Video streaming (HD) | About 5 Mbps down | Netflix's official recommended value for HD is 5 Mbps |
| Video streaming (4K) | 15–25 Mbps down | Netflix's official 4K (UHD) recommendation is 15 Mbps. Some sources set 25 Mbps as the minimum |
| Online gaming | 30 Mbps or more down / ping of 50 ms or less | Ping (response time) matters more than raw speed. For FPS titles and similar, 15 ms or less is desirable |
The figures come from: for video meetings, Zoom's official system requirements (bandwidth targets; reference explainer: NECネッツエスアイ (NEC Networks & System Integration)); for video, Netflix's official recommended speeds (reference: HighSpeedInternet); and for gaming, the general targets published by a major fiber-line provider (reference: 大阪ガス（Daigasコラム） (Osaka Gas, Daigas column)). All of these are targets for comfortable use, and the required amount changes with simultaneous household use and device performance. In a household where several people use 4K video or online meetings at the same time, choosing a property and plan that can secure several tens of Mbps of effective speed, with headroom, gives you peace of mind.
What deserves attention here is that even the VDSL method (up to 100 Mbps) can be perfectly usable depending on the use case. If one or two people mainly do video meetings and video streaming, an effective speed in the tens of Mbps rarely causes much dissatisfaction. On the other hand, if you frequently play online games, send and receive large files, or watch 4K video simultaneously, a property where you can choose the optical method is a better fit. Deciding your use case first, then choosing the property and line, is the trick to balancing cost and comfort. Owners who want to leverage the internet environment to raise occupancy may also find it useful to read what is an internet-free rental property? — where "free" refers to a building in which the internet cost is bundled into the rent, a positioning tool that differs from the tenant-pays-directly norm common in Western rentals.
Frequently asked questions (FAQ)
Q. Can I choose any internet provider I like, even in an apartment?
With an apartment (MDU) plan, you are basically limited to the providers already installed in the building. If you want to use a different company, you check whether an individual detached-house-plan contract is possible, after obtaining the owner's permission. With an "internet-ready" property, you have comparatively more room to choose your own provider. This is a notable departure from many Western markets, where a tenant can usually order from any carrier serving the address regardless of what the building "already has."
Q. If my apartment's internet is slow, how can I improve it?
The basic first step is to review your in-home environment. Replacing the Wi-Fi router, switching to a wired LAN connection, and moving the router away from things like microwave ovens can bring improvements. If it is still slow, the building is likely on the VDSL method, so consider a switch to the optical method or — if you can choose — a change to a different provider or plan.
Q. In practice, how much do the optical and VDSL methods differ in speed?
The standard maximum speeds differ by about tenfold: 1 Gbps for the optical method (up to 10 Gbps on some plans) versus 100 Mbps for the VDSL method. However, the effective speed changes with the building's equipment and the time of day, so the real difference is not always as large as the labels suggest. If there is an optical outlet on the wall it is the optical method; if a modem is connected to a telephone line it is the VDSL method — those are the telltale signs.
Q. If a property is "internet fully-equipped," can I assume its speed is safe?
The convenience is appealing, but speed is not guaranteed. A fully-equipped property splits the shared equipment among all units, so in buildings with many users the speed can drop at night. Given that you also cannot choose the line provider or speed yourself, confirming measured values and the wiring method in advance, where possible, gives you peace of mind.
Q. In a unit where construction is not possible, how do I set up internet?
If drilling a hole in the wall is difficult, a home router that simply plugs into a power outlet, or a portable pocket Wi-Fi device, becomes an option. They need no construction and are usable right away, but compared with a fiber line their speed and stability are more affected by the surroundings, so people centered on remote work or gaming should check the signal conditions in advance.
