rosiesouthern86 Hi there. If you want to use your giffgaff SIM card in Barbados, you'll need to use credit top-ups, as goodybag plans won’t work outside of the UK and EU. Please find giffgaff’s roaming prices for Barbados as follows:
However, roaming coverage cannot be guaranteed in Barbados and some services may not be available. More info on this can be viewed HERE.
Therefore, you might indeed be wise to use a local network SIM card when in Barbados instead.
Hope this helps. Many thanks.