If you are planning on staying in the city then Progresif would be the better option for it offers better rates. If you are planning on travelling around the country, then DST would be better as it offers greater coverage.
Main carriers in the country
Plans such as DSTs Easi Tourist can be bought for 15 Bruneian dollars (USD11) and includes 5 Bruneian dollars (USD3.70) credit. 20 Bruneian cents (US15 cents) is deducted per MB of data used. Progresif has a package costing 25 Bruneian dollars (USD18.50) that includes unlimited local talk time, messages and data as well as 10 minutes of international call time and 10 international messages.
Passports are required and SIM cards can be purchased at Bruneis International Airport and carriers stores.
You can top up your prepaid cards at carrier stores. e-Top-ups are also available.