Why can devices on my guest Wi-Fi not see my printer?

Not necessarily. A guest network may be separate from the network your printer uses. Some routers also prevent devices on the guest network from communicating with other devices, a setting described as access-point isolation, client isolation, or guest mode. [S1] [S2]

That separation can explain why the printer is missing even if the phone and printer both seem to be connected to Wi-Fi. The evidence here does not establish what is wrong with your particular printer, phone, or router, and a missing printer by itself does not prove that any device has failed.

Start with the least disruptive checks:

1. Confirm which Wi-Fi network the phone is using and which network the printer is configured to use. Write down the network names as displayed; do not include passwords in a message to someone else.
2. Ask the network owner whether guest devices are meant to print. A guest network can have a product-specific option for allowing access to selected shared devices, including a printer; availability depends on the router system. [S1]
3. If you can access the printer’s own display or ordinary settings, check whether it reports that it is connected to Wi-Fi. Avoid resetting it just because it is not visible to a guest device.
4. If the printer is managed by a workplace, landlord, or other organization, ask its network administrator before making changes.

These checks help distinguish a connection question from a guest-network access rule without assuming either one is the cause.

Do not turn it off broadly as a first step. Isolation can prevent devices from communicating, and router guidance for particular Google devices recommends checking the router documentation about changing isolation settings; that guidance is device-specific, not a general recommendation to disable guest protections. [S2]

Instead, look in the router’s official documentation for a way to grant access to the printer specifically. For example, Google’s guest Wi-Fi instructions describe a product-specific option to choose which shared devices guests can use, including a printer. That does not mean every router offers the same control or uses the same menu names. [S1]

If you cannot tell what a setting would expose, keep the existing separation and ask the router maker or a qualified network administrator what selective sharing options your model supports.

You can send this copyable note:

“Hi, I’m trying to print from a device connected to the guest Wi-Fi, but the printer does not appear. Could you check whether this router supports allowing guest access to this printer specifically? Please leave the guest-network protections in place unless the router documentation confirms a suitable, deliberate sharing option. If it does not support selective printer access, I can use another printing method you approve.”

For a hypothetical example, suppose a visitor’s phone is on “Guest” and the printer is on a separate home network. The owner can first check the router’s supported guest-device options. If there is no suitable selective option, the visitor can ask the owner to print the document or use another approved method. That avoids treating a broad isolation change as the default fix.

The cited guidance establishes that separation and isolation can affect device communication and that some product-specific systems offer selective access. It does not establish the right setting for every router, guarantee that enabling access will make a particular printer appear, or identify a fault in your setup.