Which caribbean island is best for diving?

[softnuance]

I will crusing St-kitt, Barbados, Ste-Lucia, St-Thomas, St-Martin.

What is the top 2 best places... for clear water, coral and fishes?

 

[ManuLani]

Depending on the local prevailing conditions they all can be spectacular.... or poor conditions.
Of these listed above , I've had the most enjoyable dives at St. Kitts with pro divers at the base of the pitons and St lucia with Iyanola dive adventures.

 

[Bryan Cunningham]

Of those you listed, probably the South West coast of St Lucia. But if going to St Maarten, Saba is much better and just a small hop away.