Most carriers drop dead between Phuket and outer islands. Here's what actually works when you're stuck on a longtail.

AIS dominance on island runs: AIS One-2-Call at HKT airport arrivals — 299 baht for 20GB/30 days. Only network with consistent signal during Phi Phi crossings and James Bond Island tours. True and Dtac go silent once you hit open water past Chalong Bay.

Maya Bay dead zone reality: Even AIS cuts out inside Maya Bay itself — Those limestone cliffs kill everything. Download offline maps before any longtail excursion or you're navigating blind.

Monsoon interference: June-October storms knock out cell towers regularly. Patong beachfront hotels lose internet for hours during heavy rain. Coffee shops on Thalang Road (Old Town) have fiber backups that stay solid.

Rawai fishing village trick: Local fishermen use VHF radios, not cell phones. If you're stuck with no signal, find the harbor master's office — They can contact emergency services via marine radio.