St Lucia, which has a population of about 170,000, opened diplomatic relations with Taiwan in 1984, when John Compton, the current prime minister, was first in power.
Taipei severed ties in 1997, when Kenny Anthony, the prime minister at the time, switched recognition to Beijing. Compton was re-elected late last year.
Twenty-five countries, including St Lucia, now recognise Taipei. Latin America, the South Pacific and Africa are the main diplomatic battlegrounds for rivals Taiwan and China, which split in 1949 at the end of a civil war.
Taiwan and China have each accused each other in the past of using "chequebook diplomacy" to lure the other's allies.
Taipei suffered a diplomatic setback when Chad switched recognition to Beijing last year.