ASEAN Beat | Diplomacy | Southeast Asia

The Dynamics of Dependence Beyond Thailand’s Immediate Neighborhood

The past year has seen considerable steps forward in the country’s relationships with Singapore and Indonesia.

Singapore’s Prime Minister Lawrence Wong (left) and Thai Prime Minister Anutin Charnvirakul take part in the fifth Thailand-Singapore Leaders’ Retreat in Bangkok, Thailand, Sep. 2, 2026.

Varying degrees of dependence – and interdependence – dictate how Thailand approaches its neighbors. Attention naturally fixates on adjacent states, not least because the poorly demarcated frontiers of mainland Southeast Asia are a hotspot for armed confrontation and illicit businesses. Drug trafficking, cyber scam operations, and unregulated rare earth mining are all concentrated in this sub-region.

But now is an opportune time to reflect on Thailand’s low-friction dynamics with Singapore and Indonesia, given their recent diplomatic momentum amid mounting global supply chain risks, and the Thai government’s pursuit of a more proactive foreign policy aimed at better communicating national interests.

Early this month, Thai Prime Minister Anutin Charnvirakul and Singaporean Prime Minister Lawrence Wong met in Bangkok for the fifth Thailand-Singapore Leaders’ Retreat – the highest-level forum for their bilateral engagement – after an 11-year hiatus. Both sides pledged greater cooperation on energy and food security, digital and physical connectivity, defense, and regional strategic matters as they prepare to chair the Association of Southeast Asian Nations (ASEAN) in alphabetical succession following the Philippines’ current term.

Thailand-Singapore ties, which the Singaporean premier described as being in “excellent shape,” have gained fresh vigor since the 60th anniversary of their diplomatic relations last September. The defense dimension stands out, with reciprocal visits by defense ministers and the top brass, and a study trip by a delegation from the Chulachomklao Royal Military Academy led by Princess Maha Chakri Sirindhorn, the sister of King Maha Vajiralongkorn.

The Thailand-Singapore defense partnership is indeed one of the most robust within ASEAN. First, Thailand and Singapore are probably Southeast Asia’s two most active participants in combined military exercises and maintain high-tempo, tri-service drills with each other on a bilateral level. Kocha Singa (army), Flash Thunder (special operations), and Air ThaiSing (air force) run annually. Singsiam (navy) is held biennially but is complemented by the annual Singapore-India-Thailand Maritime Exercise. The Cope Tiger aerial exercise alongside the United States is another one of Thailand and Singapore’s annual trilateral engagements. All this is without mentioning Cobra Gold, Southeast Asia’s largest multilateral all-domain exercise, held in Thailand every year.

Second, Thailand has provided the Singapore Armed Forces with dedicated training space as they face severe land constraints at home. Even with training areas elsewhere in the region, Thailand remains uniquely valuable for Singapore’s military. For one, access agreements with Thailand do not require carefully managing political sensitivities in the way those with Indonesia do. And, compared to Brunei, Thailand has more physical capacity to accommodate expansive maneuvers.

Third, despite several ASEAN members sourcing defense equipment from Singapore, only Thailand has procured high-value strategic assets, as data from the Stockholm International Peace Research Institute shows. In 2008, four years after Singapore transferred seven of its F-16A/B fighters to Thailand in exchange for 15 years of access to Thai training areas, the Royal Thai Navy (RTN) signed a $132 million order for an Endurance-class amphibious assault ship later christened as HTMS Angthong. The RTN’s only other amphibious ship today is HTMS Chang (Type-071E) obtained from China. In 2026, Singapore’s ST Engineering was among the RTN’s choices to supply its next-generation frigate, even though South Korea’s Hanwha Ocean won in the end. What this suggests is strong Thai confidence in Singapore’s defense standards and advances relative to the rest of ASEAN.

The dynamic of Thai geographic advantages and openness complementing Singapore’s value-added expertise promises broader........

© The Diplomat