I researched about the currencies...
St.Lucia: The unit of currency used in St. Lucia is the Eastern Caribbean Dollar (EC$) but a wide range of currencies such as US$, Canadian dollar, Euro and British pounds are freely convertible in our banks. The EC dollar is fixed to the US dollar at the rate of US$1.00 = EC$2.70 and varies in value along with it against the other world currencies.
Barbados:When planning your Barbados vacation remember that the Barbados Dollar is converted at the rate of $1.98 BDS to $1.00 U.S.
The Barbados Dollar is fixed to the U.S Dollar and does not fluctuate. Its rate to other currencies fluctuates daily based on their fluctuations relative to the U.S. Dollar.
On your travels around Barbados you will find that US currency is accepted across the island, and most stores and restaurants accept major credit cards and travellers cheques. Of course most Barbados hotels and other lodging also accept these various forms of payment.
Dominica: The local currency is the Eastern Caribbean dollar (EC$), which trades at EC$2.67 to US$1.00. Banks will offer EC$2.68 for a US$1.00 traveller's cheque. Everywhere on the island businesses accept United States Dollars, British Pounds, and Euros.
I HOPE THIS INFORMATION HELPED YOU!
sussy (sailing on Octuber 25th, 2009)