Thailand’s “Trairanga” (adopted September 1917) is a five‑stripe red‑white‑blue‑white‑red tricolour, with the blue centre band double width. Red denotes the nation/people; white Buddhism/religion; blue the monarchy and, historically, solidarity with WWI Allies. Proportion is 2:3 with strict stripe ratios; law governs protocol, precedence, half‑masting, and dignified retirement. It replaced earlier elephant‑on‑red royal ensigns to modernise and internationalise Siam’s emblem.
Thailand’s modern flag, the Trairanga (“Tricolour”), dates to 1917 and articulates nation, religion, and monarchy—the three pillars of Thai identity—through a crisp, symmetrical composition.
From Plain Red to Elephant Banners For centuries, Siam used a plain red ensign in maritime contexts, later adding devices such as the chakra and a white elephant to signal royal authority. As international trade expanded in the 19th century, these emblems served on royal and naval standards, but complexity and variability limited their suitability as a civil flag.
1916–1917 Reforms and Adoption Under King Vajiravudh (Rama VI), reforms pursued clearer international presentation and domestic cohesion. A red‑white‑red flag appeared in 1916 as a transitional design. In September 1917, the definitive Trairanga was decreed: five horizontal stripes—red, white, blue (double width), white, red—with a 2:3 aspect ratio. The blue centre honoured the monarchy and aligned Siam visually with Allied colours during World War I.
Symbolism
and Structure Red signifies the Thai nation and the land; white represents Buddhism and religious purity; blue denotes the monarchy and loyalty. The doubled central band establishes visual centrality of the crown and balances the composition.
Protocol
and Variants Regulations prescribe stripe proportions, colour shades, respectful handling, sunrise‑to‑sunset flying, half‑masting in mourning, and dignified retirement. Royal, naval, and military flags adapt elephant and chakra devices, while the civil flag remains the five‑stripe tricolour.
Continuity
in Public Life Unchanged since 1917, the Trairanga flies over ministries, schools, temples, and embassies, anchors national ceremonies, and functions as a unifying symbol through political change. Its clarity and legal standardisation have secured high recognition at home and abroad.