Just returned from going snorkeling in Bonaire with Woodwind. Again, a fantastic time.
The first stop is usually a drift snorkel. Most of the people on our trip used fins, which Woodwind supplies, so no need to bring yours. Second stop is not drift snorkeling and you'll have to do swimming.
Woodwind supplies everything you need - even shorty wet suits, masks, fins, noodles, vest, etc.
I highly recommend going with them.