From the FAQs on the home page of Coconut Bay:

"Voltage

The voltage of all electrical outlets at the resort is 220/50hz, so guests will need a converter. A british 3-pin plug (which are available for sale at any electronics store pre-travel) will suffice."

Coming from North America, you will need both an adapter to fit the plug and converter to step down the voltage. You can find them at luggage or travel accessory stores as an all-in-one or with the 2 separate pieces.

Good luck.

The electrical appliance you wish to bring to St Lucia must be labeled as 120-240 Volts and 50-60 hertz. If not, it will fry whether you have an adapter or not.

The only other solution is a transformer. These are heavy and expensive.

I do not purchase a personal appliance unless it is labeled 120-240 V and 50-60 hz

It costs nothing and can be used anywhere in the world.

Yup - very good point deepglory. Lots of more recent electronic devices are ranged voltages - cell phones and computers, etc. But not all - hair dryers and the like usually aren't. That is why bringing both the adaptor (for the plug itself) and a converter (for the voltage) is necessary. C-Bay has a few, but only a very few, you could end up having to buy one, and they are scarce around here!

Good luck OP.

Thank you very much.