Wash the cucumber and carrot thoroughly and cut them into bite-sized pieces.
Thinly slice the onion.
Sterilize a glass jar by boiling it in water and prepare it.
In a pot, add water, vinegar, sugar, salt, whole peppercorns, and bay leaves. Bring to a boil.
Once the sugar has completely dissolved, turn off the heat.
Put the prepared vegetables into the glass jar and pour the hot pickling solution over them.
Close the lid, let it cool at room temperature, then store in the refrigerator.