Back in mid-2015, Thailand made its biggest defense deal in the kingdom's history. With 1.03 billion U.S. dollars, Thailand bought three diesel-electric submarines from China, making the country the first in Southeast Asia to order Chinese submarines.

Beijing offered a package deal that no other country could match: Three brand-new submarines for the price of two – with an 11-year repayment period and a two-year warranty – plus combat systems and crew training.

In fact, the military ties between China and Thailand had gone from strength to strength ever since the country's 2014 coup, a time when the U.S. turned away from its old ally.

At a time when then U.S. president Barack Obama reacted negatively to Thailand's crisis by cutting five million U.S. dollars in military aid and downsizing their joint military exercises, China opened its arms.

Beijing's defense companies have been able to give the best price for the best products. Since 2014, the Royal Thai Armed Forces has procured a range of other products from China, including 34 armored personnel carriers, armored command vehicles, artillery locating radar and surface-to-air missiles.

In addition, top-level Thai officials have been visiting military educational institutions affiliated with the People's Liberation Army (PLA) of China. Both sides have also conducted military drills together for both navy and air forces on an annual basis.

The warming ties do not just end here.

In December 2017, construction started for Thailand's first high-speed railway from Bangkok to the northeastern province of Nakhon Ratchasima, with the help of Chinese railway talents.

Upon completion, the railway is set to link with Laos' Vientiane before reaching southwest China's Kunming up north. It is also part of China's plan for a network of links across Southeast Asia over China-proposed Belt and Road Initiative, hoping to connect China with Asia, Europe and beyond.

Read more: China-Thailand railway project: The route and key events

By this April, the first 3.5 kilometers of the high-speed railway line have been finished, Reuters reported. According to a Thai Transport Ministry official, the first section leading to Bangkok will be completed in two to three years.

In a recent interview with Xinhua, Thai Prime Minister Prayut Chan-o-cha said both sides have attached great importance to infrastructure and connectivity construction and have achieved notable results in bilateral economic cooperation.

The Thai prime minister added that thanks to the infrastructure project, the two sides have witnessed a frequent exchange of visits by high-ranking officials and deepened communication.

Twenty-one-year-old Thai Anupat Tiprat was a college drop-out, and his random scroll through pictures on Facebook changed his life.

On a poster, it said Banphai Industrial and Community Education College was admitting students who would get Chinese scholarships for rail-related majors. From there, Tiprat got the chance to study railway in central China's Wuhan, Xinhua reported.

"I feel like I am a bit closer to my dream," he told Xinhua.

Tipart is just one of the millions who are serving as bilateral cultural ambassadors. No less than 38.3 million Chinese tourists traveled to Thailand last year, accounting for 27 percent of the total.

That number is continuing to grow, amid Thailand's visa fee waiving policy to visitors from several countries, including China. To accommodate the growing tourism segment from China, Thais are starting to pick up a few words of Chinese or even learn the language.

"Officials at immigration find it helpful to know some Chinese. Private enterprises, hotels and restaurants also need staff that can speak Chinese so they can communicate with Chinese customers. Enthusiasm for learning Chinese in Thailand is growing rapidly," former Thai Deputy Prime Minister Pinit Jarusombat told China Daily.

Jarusombat hopes to see more interactions between the two sides in the years to come, since "this is the noblest form of culture," he said.