This search comes up constantly, and the reason makes sense. The neighbour's Wi-Fi signal reaches your living room at three full bars. Nothing is physically taken, and nothing visibly runs out.
The law looks at this from an entirely different angle, and the difference is worth understanding, whether you are the one tempted, or the one whose network is being used.
Note. This is an educational summary, not legal advice. For decisions affecting an actual dispute, consult a competent legal adviser.
Not about the signal, but about entering
The idea that makes people think this is acceptable: the signal already reaches here, so using it is like enjoying the light from a neighbour's lamp falling over the fence.
That comparison does not hold, and here is why.
Receiving a signal really is passive, your device listens and does nothing. But connecting is no longer passive. Your device sends a request, asks for an address, and enters the network. From that moment you are inside someone else's system, not merely receiving what is broadcast outward.
Law Number 11 of 2008 on Electronic Information and Transactions, together with its amendments, contains provisions on accessing another party's electronic system without right. A Wi-Fi network and the devices on it fall within that scope.
"But there's no password on it"
This is the most common defence, and it deserves a direct answer.
An open network is not the same as a network offered to the public. What decides the matter is whether permission was given, not whether a password exists.
| Situation | Permission? |
|---|---|
| Cafe Wi-Fi where you bought a drink | Yes, part of the service |
| A neighbour's Wi-Fi with no password | No |
| A neighbour's Wi-Fi whose password you guessed | No |
| A neighbour's Wi-Fi they shared with you | Yes |
| Public Wi-Fi provided by local government | Yes |
The third row deserves emphasis. Guessing a password, or using software to break it, is not a grey area, it sits clearly on the wrong side.
The rules that apply to networks genuinely provided for public use are different, and are covered in the guide to the rules on public Wi-Fi in Indonesia.
If it is your network being used
This side gets forgotten more often, though the risk is greater.
All traffic leaving your network is recorded under your subscription. If someone piggybacking uses it for something unlawful, the first line of enquiry points at the account holder, you.
Explaining that it was not your doing is possible, but the process is wearing and not always quick. The scope of this responsibility is set out in more detail in the guide to Wi-Fi owner liability.
Beyond that, someone inside your network is sharing a room with your computer, your printer, and your cameras. What they can see from that position is more than most people imagine.
Checking and closing it
Look at the list of connected devices
Open the router's admin page and find the active device list. Match each one against a device you recognise, the method is in the guide to blocking a Wi-Fi user.
Change the password to something long
This closes off every previous connection at once, including devices you do not recognise , guide to changing your Wi-Fi password.
Make sure the security is WPA2 or WPA3
Older settings leave a password of any length breakable, guide to WPA2 versus WPA3.
Check for other signs
An unfamiliar device that reappears after the password is changed means something deeper, guide to spotting a compromised Wi-Fi network.
One thing that is not worth doing: hiding the network name. It is often suggested as a defence against piggybacking, when in practice it makes almost no difference, guide to hiding a Wi-Fi name.
Lawful options if the need is real
If the underlying reason is cost, there are several routes that leave nobody in a difficult position.
- Talk to them and share the cost. Sharing by agreement is generally fine. Ask your neighbour to switch on a guest network for you, the separation protects both sides, guide to separating a guest network.
- Take the most basic plan. The cheapest home packages are now adequate for everyday use, guide to choosing an internet plan.
- Look for official public networks. A number of local governments provide them in public spaces. Note how to use them safely, guide to public Wi-Fi.
If the cost sharing involves many households, there is a line to watch. Sharing with one or two neighbours by agreement is one thing. Reselling access to many customers is another, and that activity falls into the field of telecommunications provision, which has its own requirements, guide to whether RT/RW Net is lawful.
Connecting to someone else's network without permission is not a grey area, and it does not become one because the network happens to be open. For the owner, leaving a network open is not merely a loss of speed, it attaches your name to whatever anyone else does from there.
Both sides are settled by the same simple things: a long password, the right security setting, and a conversation with the neighbour if there is a genuine need.
Frequently asked questions
If a neighbour's Wi-Fi has no password, is it fair game?
Not automatically. An open network is not the same as a network offered to the public. What decides the matter is whether the owner gave permission, not whether a password exists.
Which law covers this?
Law Number 11 of 2008 on Electronic Information and Transactions, together with its amendments, contains provisions on accessing another party's electronic system without right. A Wi-Fi network and the devices on it fall within that scope.
What is the risk for an owner who leaves a network open?
All traffic leaving that network is recorded under the subscriber's name. If someone uses it for something unlawful, the first line of enquiry points at the account holder, and explaining the situation is not a pleasant process.
Is it acceptable to share internet costs with a neighbour?
Sharing by mutual agreement is generally fine. Reselling access commercially to many people is different, because that activity falls into the field of telecommunications provision, which has its own requirements.
