National ensign during late Ayutthaya and Thonburi periods

1700-1790

1790-1820

State and naval ensign decreed by King Buddha Yodfa Chulaloke (Rama I)

Buddha Yodfa Chulaloke

20 March 1736 – 7 September 1809

Also known as“The Great", or Rama I

Change instituted by King Buddha Loetla Nabhalai (Rama II)

1820–1855

King Buddha Loetla Nabhalai (Rama II)

National ensign decreed by King Mongkut (Rama lV)

1855–1893

King Mongkut (Rama IV)

State flag and ensign, decreed by King Vajiravudh (Rama VI)

1912–1917

King Vajiravudh (Rama VI)

Civil ensign1917

Royal Navy Flag1917

National flag, civil and state ensign

1917–present