Hi,
I'm going to St lucia, I just want to know if atm machines widely available in castries , which will accept visa or mastercard?
thanks

There are several banks with atm machines in Castries, and elsewhere on the island that will accept visa or mastercard. If you have a debit card that reads "plus" or "interact", these are much cheaper than a credit card for cash withdrawals.
The main banks are:
Bank of St Lucia;
Royal Bank of Canada (RBC)
Canadian Imperial Bank of Commerce (CIBC) and
Canadian Bank of Nova Scotia (Scotia Bank)
I have never used a visa or mastercard for cash withdrawals, it is just far too expensive.
Thanks, i only use my debit card for emergencies
Do you know the interest you are charged for cash withdrawls from your credit card? Also what date the interest starts to accumulate?
Never, never take cash from your credt card. Much wiser to use your debit card.
Whether credit or debit cards are better depends on where you are from.
If you're from the UK, the cheapest way to get cash from an ATM outside of Europe is now via the Halifax Clarity credit card. There is no 'per transaction' charge and they use wholesale (ie good) exchange rates.
Interest starts to accumulate immediately, but we just go online immediately after drawing the cash out and transfer money from our current(checking) account to pay off the credit card, so pay just a few pence in interest. They prevent you from paying it off before you withdraw the money to totally avoid the charge.
This contrasts with debit cards that now have a 'per transaction' charge of £2+ and some of whom use really bad exchange rates.
Debit cards always used to be cheapest, but certainly aren't now for Brits outside Europe.
No matter how you draw cash -- ATM or credit card -- be sure to call the customer service for the company and let them know you'll be traveling and where to. Otherwise they may put a hold on transactions that are coming from a foreign place you don't visit regularly.