You do not need a tour to snorkel in Curaçao. With a rental car and your own mask, you can swim straight from beaches such as Playa Porto Mari, Playa Lagun and Cas Abao.
A snorkeling tour makes more sense if you want to visit several reefs in one day, snorkel with a guide, reach sites from a boat, or avoid driving the west coast yourself. There are also alternatives such as Snuba, Sea TREK and Seabob if ordinary surface snorkeling is not what you are looking for.
Below, we compare the main ways to snorkel Curaçao, where you can go independently, and when paying for a guided trip is actually worth it.