The licence was granted by the Energy Regulatory Commission, as part of a move to liberalise the gas business by opening up trade to the private sector.
The import and trade will be dealt with by B Grimm LNG Co, a subsidiary wholly owned by the mother company, said B Grimm Power's president Preeyanart Soontornwata.
She added that the gas would be used to fuel five B Grimm small power producer plants (SPPs) which are expected to begin operating in 2021-2022.
The plants are being built in the Eastern Economic Corridor, where demand for electricity to run factories is growing.