If you can't find one, carry it with you
If you can't find a trash can, put your trash in a bag and carry it with you, then throw it away at a designated place such as your home or accommodation. Even when using a trash can at a store you bought something from, follow the instructions, such as putting in only trash from items you bought at that store.
When You Can't Find a Trash Can
Put It In
Keep Carrying It
Designated Bin
Places you must not bring trash to
You must not bring household trash to trash cans at stations, convenience stores, and similar places. The bin next to a vending machine may be only for cans and PET bottles.
Check your local area's rules
Since sorting methods and collection days differ by area, check the guidance from the municipality where you live regarding household trash.