You can bring cigarettes to Brunei, but there are certain quantity restrictions.
Brunei Customs allows non-Muslims aged 17 and above to bring no more than 200 cigarettes and cigars of less than 60 grams when entering the country (each cigarette needs to pay a tax of 0.5 Wen dollars or Singapore dollars); 2 liters of spirits (1 liter per bottle) ) and 12 cans of beer (330 ml each), 60 ml of perfume, and 250 ml of perfume.
When bringing the above items into the country, you must declare them to the customs and state that they are for personal consumption only. If you carry large amounts of cash, you must declare it to Brunei Customs in accordance with regulations.