Help with the formalities to visit Barbados

Hi,

We are planning a family trip to Barbados. As the climate is same all over the year, I don't think we have to concern more about it. But, I have some other queries regarding a Barbados travel.

Do I require a visa when visiting Barbados?
If yes, then how do I apply for one?

When I read the words from experienced ones, I was wondering if non-divers can go out on the boat. I love being on the water and hearing about what they saw. So, I would like to know the kind of certification needed to dive in Barbados. Please share the details you are sure about and hope you would help with suggestions to make this Barbados travel a great one! Thanks in advance!