The ETravelSim Malaysia eSIM works in the Cameron Highlands main towns of Tanah Rata and Brinchang, on the Perhentian Islands at the main resorts, and on Tioman Island around Salang and Air Batang. Coverage softens on remote tea plantation trails, hiking paths to Mossy Forest, and on the smaller Perhentian beaches away from main resort clusters. This affects every Malaysian carrier equally because of geography. Download offline Google Maps and accommodation details before heading to the islands.