The WhiteSpace, owner of the Penguin SIM brand, is entering an agreement to rent TOT's 2100-megahertz network to add to the 850MHz network it already rents from CAT.
Penguin will begin providing mobile service on TOT's spectrum in November and plans to offer roaming on CAT's network by early next year to generate greater capacity for customers nationwide.
Penguin SIM is the most active mobile virtual network operator (MVNO) in Thailand, having launched in April 2016.
WhiteSpace chief executive Chaiyod Chirabowornkul said the MVNO model is still needed as an alternative for customers, even though competition has been intense.
An MVNO is a mobile operator that does not own a cellular network, instead renting other networks to provide service.
Penguin SIM has 300,000 active mobile users, selling 40,000 SIM cards per month.
The WhiteSpace provides 3G mobile service on CAT's 850MHz network. The company expects combined active users under the Penguin brand to double in the next year, after it launches service on TOT's network.
TOT's network will enable Penguin to offer a variety of Internet of Things solutions for customers through vendor partners increasingly being adopted by households and corporations.
Mr Chaiyod shrugged off the entry of Line Mobile, which Total Access Communication (DTAC) launched last month, saying Penguin SIM has a different target group and strategy.
He said The WhiteSpace is an MVNO for prepaid customers, primarily those in provinces. While Line Mobile's operational support is all online, Mr Chaiyod said he doesn't believe provincial customers enjoy contacting online services for help.
Additionally, Penguin positions itself in low-cost mobile services, for which customers are charged on the basis of real usage -- per second for voice services and per megabyte for internet use.
"Our main tariff is less than 20 baht per day for maximum mobile internet use," Mr Chaiyod said.
TOT senior executive vice-president Rungsun Channarukul said there are two active MVNO operators on TOT's 2100MHz network, Loxley's i-Kool and Mobile 8 Telco Thailand's BuzzMe. The two brands have about 100,000 subscribers combined.
TOT runs its own 3G service under the TOT 3G brand, with some 120,000 subscribers.
TOT had five MVNOs on its 2100MHz network, but three MVNOs have quit.
"Another company will join the MVNO market by the end of this year," Mr Rungsun said.
