NO, Brunei (wealthy sultanate on Borneo island, Malaysia maritime border, one of the world's richest countries by GDP/capita thanks to oil and gas) is outside the EU — telecom roaming is billed at high rates. The Alosea Brunei eSIM is essential to discover unique Islamic architecture (Sultan Omar Ali Saifuddien Mosque, Jame'Asr Hassanil Bolkiah Mosque), Kampong Ayer (world's largest water village, 30,000 inhabitants on stilts) or Ulu Temburong virgin forest. You connect to DST, Progresif or UNN upon landing at Bandar Seri Begawan (BWN).