But Dialog, a unit of Axiata of Malaysia has wide mobile broadband coverage as well as Mobitel, a unit of Sri Lanka Telecom.
Airtel Lanka also started mobile broadband services.
The other two operators, Etisalat and Hutch provide data services via general packet radio service (GPRS).
The tests were carried out on Symbian and Windows CE platforms to meter high speed packet access (HSPA) services of celcos, LIRNEasia said.
Stationary and on the move readings of return trip time (RTT), jitter which is the variation of RTT, packet loss and availability were carried out at points on main roads from Colombo to nearby towns of Kalutara, Negombo, Avissawella and Nittambuwa, LIRNEasia said.
The mobile broadband quality of all provincial capitals will be metered in future, Wattegama said.
"Mobile broadband users in most places in western Province can expect a reasonable quality unless a rare issue like the distance from a tower or a higher number of simultaneous users hinders it," LIRNEAsi