Thailand, officially the Kingdom of Thailand and historically known as Siam, is a country in Southeast Asia on the Indochinese Peninsula. With a population of almost 70 million, it spans 513,120 square kilometres (198,120 sq mi). Thailand is bordered to the northwest by Myanmar, to the northeast and east by Laos, to the southeast by Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the southwest by the Andaman Sea; it also shares maritime borders with Vietnam to the southeast and Indonesia and India to the southwest. Bangkok is the state capital and largest city.

Malaysia is a country in Southeast Asia. The federal constitutional monarchy consists of 13 states and three federal territories, separated by the South China Sea into two regions: Peninsular Malaysia and Borneo's East Malaysia. Peninsular Malaysia shares a land and maritime border with Thailand and maritime borders with Singapore, Vietnam, and Indonesia. East Malaysia shares land and maritime borders with Brunei and Indonesia, as well as a maritime border with the Philippines and Vietnam. Kuala Lumpur is the national capital, the country's largest city, and the seat of the legislative branch of the federal government. Putrajaya is the administrative centre, which represents the seat of both the executive branch and the judicial branch of the federal government. With a population of over 33 million, the country is the world's 43rd-most populous country. Malaysia is tropical and is one of 17 megadiverse countries; it is home to numerous endemic species. Tanjung Piai in the Malaysian state of Johor is the southernmost point of continental Eurasia.