THB · Thailand
The current Thai banknotes are Series 17, issued from 2018, carrying a portrait of King Maha Vajiralongkorn (Rama X) on the front. Series 16 notes remain legal tender and circulate alongside them. The baht is one of the currencies Indian travellers carry most, and the checks are straightforward once you know that the security thread behaves differently on the lower and higher denominations.
Features published by the Bank of Thailand.
A watermark formed within the paper shows the King's portrait together with a bright, translucent denomination numeral. It is created by varying the density of the paper fibres, so it reads as a soft gradation rather than a printed image.
How to check: Hold the note up to the light. The portrait and the numeral must be visible from both sides and must disappear entirely when the note lies flat on a table.
A thread is embedded vertically within the note carrying microprinted text and the denomination. On the 20 and 50 baht it is fully embedded in the paper. On the 100, 500 and 1000 baht it is a windowed thread that surfaces at intervals and carries a dynamic effect, so that the numerals appear to move and the colour changes as the note is tilted.
How to check: Hold the note to the light to see the thread as one continuous line, and read its microprinted text under a magnifier. On the higher denominations, tilt the note and watch the numerals on the thread move and its colour change.
Incomplete elements printed on the front and the back of the note are aligned so precisely that they combine into a complete figure, typically the denomination in Thai numerals, when the note is held to the light.
How to check: Hold the note against a light source and confirm the two halves join into one clean, complete figure with no offset or doubling.
The King's portrait, the denomination numerals and the lettering are printed by intaglio, leaving the ink standing above the surface of the paper.
How to check: Run a fingernail over the portrait and the large numerals. A genuine note gives a clearly ridged feel; a copy is flat.
On the higher denominations an element of the design is printed in optically variable ink that changes colour as the viewing angle changes.
How to check: Tilt the note under a strong light and watch for a complete change of colour across the element, rather than a metallic glitter.
Raised symbols near the edge of the note identify the denomination by touch, with a different arrangement of embossed lines for each value.
How to check: Run a fingertip along the edge of the note and confirm the marks are firmly raised, not printed flat.
The paper contains embedded fluorescent fibres, and parts of the printed design, including the denomination, fluoresce under ultraviolet light, while the paper itself stays dull.
How to check: A counter check under a UV lamp. Fibres should appear embedded in the paper rather than lying on the surface, and the note should not glow uniformly bright.
Very small text is printed in several places on the note, including within the design elements and on the security thread.
How to check: Under a magnifier the microprint should be sharp and readable; on a counterfeit it degrades into a smudge or a solid line.
What changes from one note to the next, once you have run the general checks above.
The 20 baht note is green. Its security thread is fully embedded in the paper rather than windowed, so you will not see silver dashes on the surface, hold it to the light instead to see the thread as a continuous dark line.
Check the watermark for the King's portrait with the numeral 20, and the see-through register against the light. Feel the raised intaglio print on the portrait and the tactile mark at the edge.
The 50 baht note is blue. Like the 20, its security thread is embedded rather than windowed.
Run the same checks: the watermark portrait with the numeral 50 held to the light, the see-through register, the raised intaglio print and the tactile mark at the edge.
The 100 baht note is red. From this denomination upwards the security thread is windowed: it appears as broken silver dashes on the face of the note and as a continuous line when held to the light, and tilting the note makes the numerals on it move and its colour change.
Check the watermark for the portrait with the numeral 100, the see-through register, the raised print and the tactile mark.
The 100 baht is one of the notes most commonly handled by visitors, so it is worth being confident with this one in particular.
The 500 baht note is purple. It has the windowed dynamic security thread, so tilt the note and watch the numerals on the thread move and the colour shift.
Check the colour-shifting element for a complete change of colour when tilted, along with the watermark portrait and numeral 500, the see-through register, the raised print and the tactile mark.
The 1000 baht note is grey-brown and is the highest denomination, so it is the one most worth checking in full.
Run every check together: the watermark portrait with the numeral 1000 against the light, the windowed dynamic security thread with its moving numerals and colour change, the colour-shifting element when tilted, the see-through register, the raised intaglio print and the tactile mark at the edge.
Very small shops and street vendors in Thailand often cannot change a 1000 baht note, so ask for a mix including 100s and 500s when you exchange.
Source: Bank of Thailand, banknote security features
Every note is checked at the counter. Call or WhatsApp your nearest Mythri Forex branch.
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