Will my existing UK, US, or EU SIM card provide free roaming in Brunei?

No, definitely not. Brunei is not included in typical EU, UK, or US domestic roaming agreements. Most home carriers, such as AT&T, Verizon, T-Mobile, or UK's Vodafone/O2, will apply their highest 'Rest of World' international roaming rates, which can be exorbitant, often $10-$15 per day or more. These costs can quickly add up and impact your adventure budget. An eSIMAdventures plan offers a far more economical and predictable way to stay connected in Brunei, avoiding unexpected high bills.