For a 30-90 day stay in Bali with island hopping the network matters more than the price. Only Telkomsel (50.9% market share, 97%+ population coverage) has functional 4G/LTE across Nusa Penida, the Gili Islands, Amed and the Bukit Peninsula; Indosat, XL and Tri often drop to unusable 3G there. The trap: Airalo's cheap local 'Indotel' plan runs on Indosat/Tri, NOT Telkomsel, so to get Telkomsel via Airalo you must buy a regional plan (Asialink/Discover+). Nomad's Indonesia plan uses Telkomsel by default ($39/20GB) and is the best island pick, with uncapped tethering; Saily ($21.99/10GB) also allows uncapped tethering. Holafly is unlimited-only with a 500MB/day hotspot cap, so a single HD Zoom call exhausts almost three days of tethering. The bigger long-stay issue is Indonesia's CEIR system: on day 91 it permanently blocks an unregistered phone's IMEI from every local network (a hard stop on the 180-day B211A visa), and a new SIM will not fix it. International roaming eSIMs are exempt from the CEIR block, so on a B211A the simplest fix is to use a roaming eSIM for the whole stay. Verified May 2026.