There are dolphin and whale-specific tours that don't include any snorkeling, and you can just snorkel from Black Rock which is probably one of the world's safest shoreline snorkeling locales.

Dolphins are definitely more active around Lana'i, Big Island and some parts of O'ahu, but a little less prevalent around Mau'i.[/QUOTE

No whales in mid June unfortunately. . Last snorkeling tour we had an encounter with an unhappy hammerhead. Brother in law was the last one in the boat.