Starting on the 17th of March 2020, any individual arriving in Brunei Darussalam, regardless of nationality, is required to undergo self-isolation. They will be served a Self-Isolation Notice at the border control post.
Under the Infectious Diseases Act, Chapter 204, they must remain at their primary place of residence and refrain from any outside activities for a period of 14 days from the date of arrival. Failure to comply with the Self-Isolation Notice is an offence under the law. The penalty for such offence is a fine of up to 10 thousand dollars, imprisonment up to a period of 6 months or both.
Source: Radio Television Brunei