Roaming

I'm off to the Caribbean, im visiting Several islands however I notice that for example Barbados has a cheaper roaming package than St Lucia, but if I purchase the slightly more expensive Barbados one, St Lucia is not included, how do I go about roaming for all the eastern Caribbean islands plus Aruba, Bonnie an Curacco

If your phone supports esim there are alternatives that cover regions.
It not maybe you will have to buy more than one bolt on from Lebara.

EsimDB is very handy for esim comparison for travellers for esim market.