The whale shark viewing season in Cenderawasih Bay is June-August, not because that's when the animals are there, but because that's typhoon season in Raja Ampat and several liveaboards run trips out of Manokwari into Cenderawasih then. It is very remote, and there's no way to do it without signing on to a liveaboard, which means 7-11 days at sea. Both diving and snorkeling; snorkeling out among the animals, while divers are expected to hold under the platform to observe them. The animals are there all the time, as they are habituated to indigenous fishing platforms.