Prime Minister Prayut Chan-o-cha met Saudi Crown Prince Mohammed bin Salman on Friday, signing agreements to ties in trade and investment.
Diplomatic relations between the nations were restored earlier this year after a decades-old diplomatic rift.
The leaders presided over the signing of five agreements pledging to increase trade and investment between the two countries, promote tourism and deepen cooperation in energy. They will also explore ways to promote more direct investments, a Thai government spokesman said.
The energy pact will cover petroleum, hydrogen, carbon capture and storage, renewable and low-carbon technology, the Energy Ministry said yesterday.
The agreement consists of two memoranda of understanding (MoU), the first of which covers a green hydrogen/ammonia project in Thailand. It will be carried out by the majority state-owned energy firm PTT Plc and the Electricity Generating Authority of Thailand (Egat), along with Acwa Power Co of Saudi Arabia.
The second MoU between the Ministry of Investment of Saudi Arabia and Egat Group covers various types of clean energy and energy transition.
Thailand is hoping that its improving relationship with Saudi Arabia could give it an economic boost.
Gen Prayut held bilateral talks with the crown prince on the sidelines of the Asia-Pacific Economic Cooperation (Apec) summit. Saudi Arabia was invited as a guest of the Apec host country.
"Cooperation in trade, investment and labour is already underway," government spokeswoman Rachada Dhnadirek said ahead of the meetings.
The two countries restored full diplomatic ties in January when Gen Prayut visited the country at the invitation of the crown prince.
Saudi Arabia downgraded ties in 1989 following a row over the theft of about US$20 million (716 million baht) worth of jewels by Kriengkrai Techamong, a Thai janitor working in the palace of a Saudi prince, in what became known as the "Blue Diamond Affair".
A large number of the gems, including a rare blue diamond, were never recovered. The theft remains an unsolved mystery and was followed by the execution-style murder in Thailand of three Saudi diplomats.
"The restoration of ties has mutual benefits for both countries," the crown prince said, adding that investment, infrastructure and public health were important areas.
"Overcoming the Blue Diamond issue is a net positive for both countries," said Ben Kiatkwankul, partner at the Maverick Consulting Group.
Saudi Arabia is seeking to diversify the economy away from oil into industries like food and agriculture, which makes Thailand a good partner, he said, while Thailand stands to benefit from energy-related projects and medical tourism.
Since January, exchanges between the two countries have included an agreement between state-owned energy firms Saudi Aramco and PTT Plc for cooperation in carbon capture and crude oil sourcing.