Thai Customs draws a line between two different things: goods that are prohibited outright, and goods that are restricted but importable with the right paperwork. The distinction matters, because most of what trips up ordinary travelers falls into the second category — permit-eligible, not banned — and the permit-issuing authority differs by what you’re carrying.
Thai Customs defines the category without listing what is in it
Thai Customs states the general definition plainly: “Prohibited Goods are goods for which either the import into or export out of Thailand are prohibited.” That is a category definition, not a list. The page states that definition and then moves on. It does not set out which items sit inside “Prohibited Goods”, so we are not going to print a list of examples we cannot point you to on the Customs page itself. A partial list would be worse than none: you would read it as complete.
One specific category is named as excluded from ordinary import or export, and it reads as an outright restriction rather than a permit-eligible one: “Reserved animals or CITES-listed wildlife” are not to be brought into or out of Thailand. The source does not describe a permit path for this category the way it does for the restricted goods below.
Restricted goods: importable, with a permit from a specific authority
Below the general prohibition, Thai Customs names a set of categories that are restricted rather than banned — each requires written permission from a specific government body, not an outright refusal at the border.
Cultural and religious items. Buddha images, artifacts and objects, and antiques require a permit from the Fine Arts Department.
Weapons. Guns, bullets, explosives, and items equivalent to guns require a permit from the Department of Provincial Administration, under the Ministry of Interior.
Plants. Plants and their parts require a permit from the Department of Agriculture.
Live animals. Living animals and carcasses require a permit from the Department of Livestock Development.
Food, medicine, and related consumer goods. Food, medicine, cosmetics, and food supplements require a permit from the Food and Drug Administration.
Tobacco and alcohol. Cigarettes, tobacco, and alcoholic beverages require a permit from the Excise Department.
For all six of these categories, the source’s own wording is the bare category name — for instance, “Guns, bullets, explosives, and the equivalents to guns” and “Food, medicine, cosmetics and food supplement” — with a responsible authority attached to each category in the source. None of these six is described as banned outright the way “Prohibited Goods” is; each has a named agency you can approach for permission.
How to actually apply for any of the six permits isn’t said
This source does not describe the actual permit application process for any of the six restricted categories — how to apply, what it costs, or how long it takes with the Fine Arts Department, the Department of Agriculture, or any of the other four agencies named above. It also does not give a complete itemized list under “Prohibited Goods” beyond the CITES and reserved-wildlife category — Thai Customs does not publish one — and it does not state what happens if a restricted item crosses the border without the required permit.
If you are carrying anything that plausibly falls into one of these six restricted categories — an old religious artifact, a firearm, plant material, a live animal, medication in quantity, or alcohol and tobacco beyond an ordinary personal allowance — the permit application has to happen with the named agency before you travel, not at the border itself.