During the reign of King Rama III, cowries and pod duang (bullet money) were used for trade between Thailand and other countries. However, copper tokens were used abroad. As a result, King Rama III issued an order to bring three types of copper tokens from England to Thailand as an example in 1835 (Chula Sakarat Thai Minor Era 1197 or B.E. 2378). However, the King was not satisfied with the patterns for the tokens, so they were not issued. Still, his attempt to use a flat round coin like the ones used internationally eventually prevailed. The end of his reign was approaching, however, before this was successfully put into practice. During the reign of King Rama IV, trade between Thailand and other countries flourished. More foreign merchants came to Thailand to do business and exchanged their coins for pod duang issued by the Thai government so that they could, in turn, used the pod duang to buy Thai products. However, because of the fact that the pod duang was handmade, it was impossible to manufacture sufficient quantities. This discouraged the growth of trade in Thailand. Consequently, King Rama IV issued an order to replace pod duang with coins. In 1856, an experiment was conducted to produce a flat round coin like the ones used internationally. This was done by hammering the metal into a flat sheet, molding it in the shape of a flat round coin with the desired size and weight, and then hand-stamping it, called hand-hammering method. But it took too long to produce each coin using this process and the coins produced were not of equal quality. In addition, foreign coins were also stamped in order to make Thais accept these coins. In 1857, King Rama IV issued a royal order for the Thai diplomatic corps visit the court of Queen Victoria of England. Queen Victoria, in return, sent as a royal gift to King Rama IV of Thailand, a small man-powered minting machine of the screw press type. King Rama IV then ordered the first coins to be manufactured by machine, called the Royal Gift Coins. At the same time, the diplomatic corps ordered a steam-powered minting machined from Taylor Co., Ltd., at the end of 1858. King Rama IV then ordered the construction of a mint in front of the Royal Treasury in the Grand Palace. Installation of the machine was completed and the mint opened in 1860, with the royally-bestowed name of the Sitthikarn Mint. It can be said then that this is the first time that a flat coin like the ones being used internationally was produced in Thailand. Later, even after these coins had been issued, the pod duang was still used. but without production ceased. The Ministry of the Great Treasury in 1895 found that there were six currency units in Mongkut Seals, namely 2-baht, 1-baht, 2-salung, 1-salung, 1-fuang, and 2-pai coins. But production was not sufficient for demand. In addition to these, there were 1-tamlung, half-tamlung, and half-fuang coins, but they were not in common circulation. King Rama IV can thus be considered as the King of Thailand who revolutionized Thai currency by shifting from the use pod duang or round money used since ancient times to coins or flat coins like the ones used internationally.
During the reign of King Rama V, in 1898, a royal order was issued to modify the currency system used from chang, tamlung, baht, salung, and fuang, to a system that uses baht and satang, in which 100 satang equales 1 baht . This has remained the currency system used in Thailand. Moreover, the King graciously allowed his royal portrait to be stamped on the surface of the coins. This was the first time that the royal portrait of the reigning king was stamped on the obverse of coins. During the reign of His Majesty King Bhumibol Adulyadej, the manufacture of various types of coins using copper and coins, bearing the royal portrait was started—the Coat-of Arms in 1950, the first 5-baht coins in 1972, the first 10-baht coins in 1988. Coins currently minted in Thailand fall into three categories: coins in common circulation, commemorative coins and medals.
1. Coins in Common Circulation: These are the coins used in everyday transactions. There are nine denominations, namely 10 b5 baht, 2 baht, 1 baht, 50 satang, 25 satang, 10 satang, 5 satang, and 1 satang. However, only six denominations are in use in the economic system, namely 10 baht, 5 baht, 2 baht, 1 baht, 50 satang, and 25 satang. The 10- satang, 5- satang, and 1-satang coins are used for accounting purposes only.
2. Commemorative Coins: Commemorative coins are coins produced for important occasions related to the nation, religion, and the monarchy, or important international events only. There are two types of commemorative coin which are polished (proof) and unpolished. The difference between coins in common circulation and commemorative coins is in the layout of the pattern on the front and back sides of the coins. For coins in common circulation, the layout employed is American Turning. This means that the pattern on the back is vertical. For commemorative coins, the layout employed is European Turning. This means that the pattern on the back is horizontal.
3. Medals: Medals refers to the coins produced for important occasions only. Medals are, however, different from commemorative coins because they do not have a face value. Moreover, since they are not money, they are not legal tender.