Do I need a guide for snorkeling at Pigeon Island?
You do not strictly have to hire a private guide for snorkelling at Pigeon Island, but you still need to buy an entrance ticket for the national park and arrange a boat transfer. In practice, most boat operators provide basic snorkelling equipment and then point out the most promising reef pockets.
Going without a guide is totally doable if you stay inside the designated swimming zones. However, bringing a local guide can really improve the overall experience. People who spot wildlife for a living know where blacktip reef sharks and sea turtles tend to feed. Plus, a guide helps make sure visitors do not accidentally harm the fragile coral landscape, and they keep everything aligned with the marine park conservation rules, which are enforced quite strictly.