did a whale watching tour at vallarta adventures. We chose the morning tour. Had to arrive at 700. tour left around 745. But they had food, and drinks to pass the time. They put 30 people in a raft/speedboat. Not sure what they call it exactly, but still room to see everything. The boats are relatively small for 30 people, but they are fast, which is a plus. The reason being that they go all around the bay looking for active whales. We would observe one group of whales for 10-15 minutes, then speed off to another location. We saw about 6 different groups of whales, and finally the last group had a whale doing several spectacular breaches. They also have communication telling them where the whale groups are, so not just random wandering.
FAIR WARNING; the boats have no bathrooms, so don't drink a lot of coffee before you go for the 3 hour tour. They ask you if you have back issues. Probably not a bad idea to say yes. We were seated near the back of the boat, with a lot less bouncing over the waves. That's the other reason for going in the morning. The wind and waves are much bigger in the afternoon.
Good experience. Whale watching is seasonal with jan, feb best.