Wi-fi is common in hotels, hostels, restaurants and cafes across the touristed areas of Sri Lanka. Travelers can also purchase a tourist SIM card for the duration of their Sri Lanka tour if they wish to stay connected.
Both Dialog and Mobitel offer tourist SIM packages that are valid for 30 days. Both have good 4G coverage across major towns and cities, though in some rural areas the connection may be limited or non-existent. The SIMs can be bought at the airport or in any major town but be sure to check that your phone has been unlocked before purchasing one.
Mobitel offer a prepaid tourist SIM with 1.5GB or 3GB of data for 499/999 Sri Lankan rupees (USD 2.75/5.50). This can be topped up at any Mobitel shop, convenience store or street stall displaying the Mobitel logo.