The currency in Saint Lucia is the Eastern Caribbean Dollar. There are ATMs in the major towns, and banks are open on week days, offering the best exchange rates. Hotels also exchange money but the rates will not be so favourable. US Dollars are also very widely accepted so a combination of dollars and cash to exchange is a great way to prepare for your trip.
The official language of Saint Lucia is English whilst French Creole is also spoken. Most of the island's inhabitants will speak English well.
+1758 for Saint Lucia, there are no area codes on the island so simply dial the local number afterwards.
Crime is pretty low on the island and the main danger you will encounter is sunburn, so remember to take plenty of high SPF cream with you and apply regularly, as well as aftersun and mosquito repellent for the evenings.
UK passport holders may stay in Saint Lucia for up to 42 days without a visa, though passports must be valid for six months on entry