The SEC infrastructure will span Chumphon, Ranong, Surat Thani and Nakhon Si Thammarat, said deputy government spokesperson Ratchada Thanadirek.
It covers a Bt10-billion seaport in Ranong province, a Bt10-billion double-track rail linking Chumphon and Ranong provinces, oil pipelines, bridges and road investments.
The completed SEC will link up with the Eastern Economic Corridor to forge a massive trade hub joining the Pacific and Indian oceans.
The Ranong seaport will open a trade route to southern Asia, while upgrades to airports in the four provinces will forge a Gulf and Andaman tourism gateway.
Short-term development from 2019-2022 will be followed by a long-term plan from 2023 for a total of 111 projects worth Bt102.41 billion.