Can one tag hold two networks?
It can hold two records, and the phone acts on the first it can handle, so the second is decoration. Two separate tags or a single page listing both are the arrangements that actually work, and the page is usually better.
The phone takes the first
A tag can carry several records, and the system acts on the first one it knows how to handle.
Two Wi-Fi records means one network is joined and the other is ignored, consistently, with the choice made by order rather than by the user.
There is no mechanism for the tag to offer a choice, because a tag has no logic and the phone is not asking.
So stacking records is not a way to present options. It is a way to carry an option nobody sees.
Two tags
One tag per network, labelled, is the straightforward answer.
Keep them apart, since two tags close together compete for the same field and the result depends on millimetres.
Label them clearly, because two identical looking tags side by side is a guessing game.
This works and it doubles the objects, which for two networks in a home is usually fine and for a property with several rooms is not.
One page
Write one address, leading to a page listing both networks with their passwords and a code for each.
The guest sees the choice, reads the one they need, and the arrangement works on every phone rather than one platform.
You can also explain the difference, which two tags cannot: which network is faster, which reaches the garden, which one to use for a television.
The cost is coverage at the moment of the tap, which is the recurring objection to every page based Wi-Fi solution.
Why people ask
Usually because there are two bands with different names, which is a configuration detail guests should not have to think about.
Where the router allows it, giving both bands the same name removes the question entirely and is better than any tag arrangement.
Sometimes because there is a guest network and a main one, in which case only the guest network belongs on a tag at all.
And sometimes because there are genuinely two properties or two areas, which is the case where two labelled tags is the right answer.
Frequently asked questions
What happens with two Wi-Fi records on one tag?
The phone joins the first it can handle and ignores the second. There is no way for the tag to offer a choice.
Can I put two tags side by side?
Keep them apart, since two tags in the same field compete and the result depends on position. Separate and label them.
What about two bands with different names?
Give both bands the same name in the router where possible. That removes the question rather than working around it.
Is a page better than two tags?
Usually, because it shows the choice, explains the difference and works on every phone. It needs coverage at the moment of the tap.