Maldives joined GATT before the WTO existed, and came into the Indian Ocean Rim Association long after its founding members
Background
The World Trade Organization's member information page, Maldives and the WTO, states that the country has been a member of GATT since 19 April 1983 and a member of WTO since 31 May 1995, within the first year of the organisation's work. The Indian Ocean Rim Association's member states page lists each member with the year it came in: the Republic of Maldives appears with 2018. The Republic of India, the Republic of Indonesia, Malaysia, the Republic of Mauritius, the Republic of South Africa and the Democratic Socialist Republic of Sri Lanka all carry 1997, the year the association was formed, and only the French Republic, at 2020, came in later than the Maldives.
In plain words
GATT General Agreement on Tariffs and Trade — The post-war trade agreement whose work the World Trade Organization took over in 1995.
IORA Indian Ocean Rim Association — A regional grouping of states bordering the Indian Ocean, formed in 1997.