Service revenue for mobile business grew just 2% on average last year compared with 5% growth in 2017, mainly due to intense competition in the second half of last year, especially from unlimited maximum speed packages.
Competition via unlimited packages saw average revenue per user (ARPU) drop for the big three mobile operators, pulling down their service revenue growth in the second half.
Pisut Namvijitvong, a senior analyst at Kasikorn Securities, said the growth of service revenue in the mobile market in the first half of 2018 averaged 4-6% but declined to 1% in the last quarter.
Revenue this year is expected to increase 3-4% on average, thanks to the major operators' decision to remove some unlimited maximum speed packages in the fourth quarter last year.
Better signs of service revenue growth will be seen from the second half this year, Mr Pisut said.
He said data service consumption has been increasing constantly year-on-year. Mobile users in Thailand were consuming 10.5 gigabytes per month per user by the end of 2018, compared with 7GB at the end of 2017.
In the overall market last year, more than 60% of service revenue for the three major operators was generated by data services, while the rest was from voice services.
Some 70% of mobile users in the country are on 4G wireless broadband networks.
Mr Pisut said the increasing use of mobile data services, especially over-the-top services on telecom networks, will be a major source of service revenue for mobile operators this year, especially through live content and video on demand.
The major operators will increasingly attract customers spending time on digital services, another way to increase their ARPU.
The analyst believes that if the government invokes Section 44 to ease the financial burden of the three major operators by extending the payment terms for 900-megahertz licences, market sentiment for their stocks will improve.
On the contrary, if major operators participate in the planned auction of 5G licences this year, their stock prices will fall sharply, he said.
Mr Pisut said the auction plan for 5G licences this year is too rushed -- the appropriate time is the last quarter in 2020.
"There have to be real business cases for 5G service," he said. "Rushed 5G investment won't benefit Thai telecom providers, as the market is still evaluating the potential revenue and returns of investment."
On Friday, True Corporation reported a net profit of 7 billion baht in 2018 on continued growth of revenue and earnings before interest, tax, depreciation and amortisation (ebitda). True also credited productivity enhancement and assets sold to the Digital Telecommunications Infrastructure Fund for the higher profit.
Consolidated service revenue was at a record-high 101.8 billion baht in 2018, a 4.9% increase year-on-year.
This, combined with continued cost optimisation and gains from asset sales to the Digital Telecommunications Infrastructure Fund (DIF), drove ebitda up 40.3% year-on-year to 56 billion baht in 2018.
On Friday, True's board of directors approved a dividend payment of about 3 billion baht (0.09 baht per share), subject to approval by shareholders at the annual general meeting in April.
In 2018, True gained 2 million subscribers, expanding the total subscriber base to 29.2 million. This drove TrueMove H's service revenue up 7.3% year-on-year compared with a 0.1% contraction of the other major players combined.
TrueVisions' service revenue grew 8.7% year-on-year to 13.3 billion baht in 2018, driven by entertainment revenue and the 2018 Fifa World Cup broadcast.
TrueOnline's broadband revenue increased 11.2% in 2018 compared with 2017, with the business capturing 332,000 subscribers and expanding the broadband subscriber base to 3.5 million.