Best SIM card for tourists in Sri Lanka — which network has the best data coverage?

Worked in telecom here for 10 years. Definitive answer for 2025:

Dialog is the best choice for tourists. Here's the full breakdown:

At the airport:
- All three operators (Dialog, Mobitel, Airtel) have counters in arrivals at BIA
- Dialog tourist SIM: LKR 500–1,500 depending on package (1 GB to 10 GB data bundles available)
- Open 24 hours — you can get it the moment you land
- Yes, passport required for registration (mandatory by TRCSL regulation)

Coverage comparison:
- Dialog: best 4G coverage nationwide including hill country, east coast, and remote areas. This is not even close.
- Mobitel: good in Colombo and major cities, drops significantly in Ella and Arugam Bay
- Airtel: competitive pricing but weakest rural coverage of the three

Tourist packages vs regular SIM:
- Tourist packages are marginally better value and come pre-registered
- You can also buy a regular SIM and add data bundles — often cheaper for longer stays (14+ days)
- For a 1–2 week trip: tourist package. For longer: regular SIM + bundles

Data speeds:
- Dialog 4G in Colombo: 20–50 Mbps typical
- Dialog 4G in Ella: 5–15 Mbps (sufficient for maps, messaging, video calls)
- In very remote areas (Knuckles range, deep jungle): expect 2G/3G only — no operator solves this

Recommended package: Dialog "Tourist SIM" with 6 GB data for LKR 990 — valid 30 days, covers a typical trip comfortably.