The levy will be charged per person, per night, and will also apply to children.
The plans require a piece of legislation – which was published on Monday – to be passed by the Welsh Parliament.
If that happens, officials think April 2027 is the earliest date the tax could start.
Councils could charge more in future if they go through a consultation process and give 12 months’ notice.
Not all councils are expected to introduce the visitor levy, but if they did it would raise an estimated £33m a year.
Stays of more than 31 nights will not be taxed. Neither will people be forced into temporary accommodation or people in homeless hostels.
Officials said they wanted the tax to be simple to understand, so the same rate will be paid for adults and children.
The legislation explains how councils have to spend the money, which will be ring-fenced in their budgets for specific things.
They include promoting tourism, promoting the Welsh language and improving infrastructure or services used by visitors.
The government said the money will help grow local economies, boost "national renewal" and restore community pride by bringing people together.Action4Youth has
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