Krause, Chester L., and Clifford Mishler (خطای عبارت: نویسه نقطهگذاری شناخته نشده «1»). Unrecognized date. Please see Template:Numis cite SCWC for available dates.. Krause Publications. Check date values in: |year= (help); External link in |title= (help)نگهداری یادکرد:نامهای متعدد:فهرست نویسندگان (link)
In the 18th and 19th century, the riyal was traditionally associated with the Maria Theresa thaler, currency that was widely in use in Yemen owing to the Mocha coffee trade with the French, and a Yemeni request that its produce be paid with thalers.
As Yemen progressed, it developed its own legal currency. After the union between the North (the Yemen Arab Republic) and the South (the People's Democratic Republic of Yemen) in 1990, both the northern rial and the southern dinar remained legal tender during a transitional period, with 1 dinar exchanged for 26 rials. On 11 June 1996, the dinar was withdrawn from circulation. In 1993, the first coins were issued for the Republic of Yemen. The value of the Yemeni rial against the United States dollar dropped significantly compared to 12.01 rials per dollar in early the 1990s. Since the mid-1990s the Yemeni rial has been freely convertible. Though it dropped from YER 20 to approximately YER 215 against the U.S. dollar since then, the rial has been stable for several years. However, since 2010 the Central Bank of Yemen had to intervene several times, resulting in a serious decline of foreign reserves. By late 2013, the Economic Intelligence Unit expects reserves to decline to approximately 1.3 months of imports over the following years, despite information that Saudi Arabia would transfer $1 billion to the Yemeni Central Bank. Due to the war, the exchange rate for the Yemeni rial has hovered between 470 to 500 Yemeni rials for 1 US dollar.
When Yemen unified, coins had been issued in North Yemen in denominations of 1, 5, 10, 25 and 50 fils and 1 rial. The fils denominations have all disappeared from circulation. In 1993, new coins were introduced by the Central Bank of Yemen in denominations of 1 and 5 rials. These were followed by 10 rials coins in 1995 and 20 rials in 2004.
At the time of unification, Central Bank of Yemen notes in circulation were 1, 5, 10, 20, 50 and 100 rials. In 1993, the 1 and 5 rials notes were replaced by coins, with the same happening to the 10 rials notes in 1995. In 1996, 200 rials notes were introduced, followed by 500 rials in 1997 and 1000 rials in 1998. The 20 rials notes were replaced by coins in 2004. In addition, a 250 rial banknote was issued on November 14, 2009. In 2017, the Central Bank of Yemen, now relocated in Aden, its interim capital due to the civil war, issued 500 and 1,000 rials banknotes with revised security features and different size dimensions. In 2018, the Central Bank of Yemen reintroduced the 200 rials banknote and has issued a new 100 rials banknote.