Foreign nationals of the following countries/territories can enter Brunei visa-free as long as they present a passport valid for at least 6 months:
For up to 90 days: All European Union member states (except for Croatia passport), United States
For up to 30 days: Australia, Kuwait, Iceland, Malaysia, New Zealand, Norway, Oman, San Marino, Singapore, South Korea, Ukraine and the United Arab Emirates
For up to 14 days: Cambodia, Canada, China (including Hong Kong SAR and Macao SAR), Japan, Indonesia, Laos, Liechtenstein, Maldives, Peru, Philippines, Switzerland, Thailand and Vietnam
Nationals of Israel will be refused entry, due to no diplomatic relations, but other passports containing Israeli stamps and visas will not be an issue for entry.
Citizens of Bahrain, Qatar and Taiwan can also obtain a visa on arrival for 14 days. These citizens can obtain a visa on arrival for B$20 or a 3 day transit Visa for B$5. Immigration officers at Sungei Tujoh between Miri and Kual Belait will not accept payment for a visa on arrival other than in Brunei or Singapore dollars; there is no ATM and cheques are not accepted.
Proof of return or onward travel is required to check in for your flight to Brunei. If you plan to leave by ferry you will need to purchase a cheap flight out of Brunei before you arrive there.
Those who need a visa must apply in advance at a Brunei embassy, where processing can take up to 3 days and costs B$20 for a single entry visa. See Brunei Immigration Department (http://www.immigration.gov.bn/visiting.htm) for the latest details.
If you require a visa to enter Brunei, you might be able to apply for one at a British embassy, high commission or consulate in the country where you legally reside if there is no Bruneian foreign mission. For example, the British embassies in Addis Ababa (http://www.ukba.homeoffice.gov.uk/countries/ethiopia/commonwealth-bots/?langname=null) and Belgrade (http://www.ukba.homeoffice.gov.uk/countries/serbia/commonwealth-bots/?langname=null) accept Bruneian visa applications (this list is not exhaustive). British diplomatic posts charge £50 to process a Bruneian visa application and an extra £70 if the authorities in Brunei require the visa application to be referred to them. The authorities in Brunei can also decide to charge an additional fee if they correspond with you directly.