They absolutely do. Tarrifs are paid at point of import not point of sale, and who the heck wants to put something on a container ship for a month of transit not knowing if you can even afford the customs charges at the end before you sell it, or won't take a loss because surprise a week after paying tarrifs are now cancelled.
Underrated comment. People don’t understand global trade and logistics (understandably so- it’s all very complicated and there are multiple middlemen involved between the factory in China and the company in the U.S. buying the goods to resell - they of course being yet another middleman).
Assuming it's not wildly different over there in the US, goods must be declared when the goods is at the border if you wish to use or transfer the goods, and tariffs must be paid. For a ship this will be the port, at least that's how it is here.
Alternatively you can put the goods in a bonded warehouse[1], and leave it there until you wish to use it or transfer it to someone else. It's not free, but it allows you to postpone the declaration, and hence payment of tariffs, until you take the goods out of the bonded warehouse.
Typically a bonded warehouse requires physical security, paperwork and a bank guarantee to prevent goods disappearing, so it isn't free to keep goods there.
That's the same thing. When you want to import goods, you provide information to the customs officials at the location those goods enter the country saying:
* Here's what I'm importing
* Here's where I'm importing it from
* Here's the value
Then you pay a bill based on that value and the tariff, and they let your goods clear customs and get loaded onto a truck to go wherever you want them to go in the US.
If you're shipping something by boat (like most goods), the "point of import" is the port.
Note: this is all actually much more complicated and individualized than I described because of networks of middlemen, logistics companies, distributors, manufacturers and lawyers.
