No, MobiMatter does not provide an unlimited‑data eSIM plan for Brunei. Their catalog for Brunei consists of fixed data plans with caps such as 50 GB for 180 days, 26 GB for 365 days, 20 GB for 365 days, 13 GB for 365 days, and a 10 GB plan valid for 30 days. These fixed‑data bundles allow tethering and cover Brunei, but each comes with a set data limit and a defined validity period. Travelers who use data extensively may find the larger fixed bundles, like the 50 GB 180‑day plan, more economical than purchasing a series of pay‑as‑you‑go top‑ups, although the choice depends on individual usage patterns.