The Andaman Sea
Andaman Sea
Thailand has a southern border with Burma.
Burma
Chiangmai is in the north of Thailand and it's near Burma
Burma, or the Republic of the Union of Myanmar has two seas on which it has a coastline, the Bay of Bengal to the southwest, with the Andaman Sea on its southern side.
Thailand
India
The coast of countries and/or islands are near the sea. It depends on which sea you are talking about.
It's bordered by India all the way and it is just a bit bordered with Burma.
Thailand is bordered by Cambodia, Malaysia, Laos, Myanmar (formerly Burma).
China is near the East China Sea and the South China Sea.
The Arafura Sea and the Timor sea are both near Darwin.