Bangar is the administrative centre of the Temburong District of Brunei. The quiet small town is relatively isolated as Temburong is separated from the main part of the country (where the capital Bandar Seri Begawan is located) by Sarawak's Limbang district.
Temburong is not very developed and as such, still has a lot of pristine rainforest. The Ulu Temburong National Park and the Batu Apoi Forest Reserve are excellent for experiencing the jungle.
Speed boats between Bandar Seri Begawan and Bangar run from 7am to 5pm. One way fares are $6 and the journey takes 45 minutes. The ride is quite interesting as the boats weave through the many river channels at the mouth of the Temburong and Brunei Rivers. Boats dock at the main jetty in town while in Bandar, they leave from the jetty near the foodstalls at Jalan Residency just east of the city centre across the Sungai Kianggeh bridge.
As Temburong is separated from the rest of Brunei by Sarawak, you will have to go through Malaysian territory (and past through four sets of immigration checkpoints) to travel from Bandar Seri Begawan to Bangar. A main road runs from the Sarawak border at Puni (Pandaruan on the Sarawak side) in the west through Bangar (Puni to Bangar: 5km), to the Labu border crossing in the east (Labu to Bangar: 20km), where the road continues to Lawas. At Puni, there is a ferry bringing vehicles (RM8 or B$4) across the Pandaruan River to the main road to Limbang 14km away. From Limbang, you can proceed to Bandar Seri Begawan via the Kuala Lurah-Tedungan border checkpoint.
Immigration formalities for those coming from Bandar Seri Begawan and Limbang have become easier with the opening of the Malaysian immigration checkpoint at Pandaruan near the ferry landing since June 2007. Previously, you had to get your Malaysian exit stamp at Limbang Wharf before going to Pandaruan. The Brunei checkpoint is about 600m from the ferry landing, and occupies a wooden one-storey building on the right (south) side of the road.
If coming from Lawas, you will have to get your Malaysia exit stamp at the Mengkalap Immigration and Customs office at Trusan before proceeding to the actual border about 8km away. The immigration office is located at a shoplot off the main road just east of the Trusan River ferry. Brunei's Labu checkpoint is at the actual border.
Like buses, strict Bruneian laws prevent Malaysian taxis from bringing passengers into Temburong. From Limbang, you will have to catch a taxi to Pandaruan, cross the river by ferry or boat, then catch a Bruneian taxi to Bangar. If you are coming from Bandar Seri Begawan, you will have to find your way to Limbang first. Coming from the east, taxis run from Lawas to the Labu border checkpoint via Trusan (where you have to get your Malaysian exit stamp). Change to a Bruneian taxi at Labu to get to Bangar.
Bangar is small enough for you to walk around, although it could be quite a hike in the hot sun to get to the administrative offices across the river from the commercial area.
Temburong basically has two main roads, one stretching from its eastern border with Sarawak at Puni, through Bangar, to the western border, again with Sarawak, at Labu, a total of about 25km. The other main road runs south from Bangar to Batang Duri.
You will have to resort to taxis to move around in Temburong if you do not have your own set of wheels. There are no buses. Taxis can cost a bit - Bangar to Labu is about B$30.
You can also hire bicycles from the Maryani Camping Shop at Bangar for B$30 dollars a day.