The paʻanga is not convertible and is pegged to a basket of currencies comprising the Australian, New Zealand, and United States dollars and the Japanese yen.

[3][4] Mariner also passed down the following statement of Fīnau ʻUlukālala as he began to understand the value of these pieces to the European sailors:[4] When Tonga introduced decimal currency, it decided not to call the main unit the dollar because the native word, tola, translated into a pig's snout, the soft end of a coconut, or, in vulgar language, a mouth.

[citation needed] Official exchange rates are released daily by the National Reserve Bank of Tonga.

In 1975, a new series of coins was issued, themed around FAO and food production and featuring a new portrait style effigy of the king.

In 2011, commercial demand for 20 and 50 seniti prompted these denominations to be issued featuring the effigy of Tupou IV posthumous, who had died in 2006.

A new obverse design for George Tupou V had not yet been made or selected at this time, possibly due to increased health concerns regarding the latter monarch, who died in March 2012.

For a brief period, some of the higher denomination coinage from the 1967–1968 series was "countermarked" with commemoration stamps that were added to the coin after being struck.

The one and two seniti coins are still valid but are becoming less common in circulation due to high production cost and low value and may only be readily available for months after a release by the banks.

The reverse designs were Tu'i Malila (a radiated tortoise presented to the Tongan royal family by Captain Cook in 1777) on the 1 and 2 seniti, wheat sheaves and a stylized depiction of the constellation Crux on the 5 and 10 seniti, and the Royal Tongan coat of arms on the higher denominations.

From 1968, the portrait of King Taufa'ahau Tupou IV appeared, facing right, with the first year issue commemorating the coronation event.

Since 1975, all coins have borne the word "Tonga" on the obverse and the inscription "Fakalahi meʻakai" (Tongan: "Grow more food") and the denomination on the reverse.

In 1967, notes (bearing the portrait of Queen Salote Tupou III) were introduced by the government in denominations of 1⁄2, 1, 2, 5 and 10 paʻanga.

The reverse is in English language and shows typical motives and landmarks of Tonga: the Haʻamonga ʻa Maui Trilithon, a humpback whale, burial mounds, school students and rugby players, the royal palace, the Tongan Development Bank, the Port of Vavaʻu (twice, once depicted as it was around 1900, and the other in contemporary depiction), and ngatu making.

[9][10] On 4 December 2023, the National Reserve Bank of Tonga introduced a new family of six banknotes to commemorate the birthday of the Kingdom’s moderniser King Tupou I.