Went on a "Swimming with the Whales and Dolphins" excursion and had a great time! One of the guides used another guest's GoPro to film the whale and calf we saw on the second of two sightings. To see the whales the ship had to stop at least 100 meters from the whale and we then had to swim at least 50 meters, usually much more I think, to see the whale.
Click on the picture above to see the photo album that contains a video of the mother and calf.
In both of our sightings there was a mother and calf. This being the end of the season I think that's primarily who is left at this time of year. Most of the others have already headed to the Antarctic for the southern hemisphere summer. Since we saw the whales from the other side, away from the boat, we must have swam more than 100 meters, maybe more like 150 meters. The second swim had fairly high swells, maybe up to 5 feet making it even more challenging. If I do this again I'll use the fins provided by the tour company which would provide more propulsion. My snorkeling fins are fairly short, which is more convenient for packing. They're also good for being around coral in shallow water so you have less chance of brushing against the coral. But I don't think they provide as much propulsion.
Had heard that some whales go to the Arctic and some go to the Antarctic but never heard what makes a lot of sense: they'll always be in the Arctic or Antarctic in what is the summer season for that hemisphere. Conversely, during the "winter" for that hemisphere, they'll be in the part of the world where it's warmer, that being near the equator, but closest to either the antarctic or arctic, meaning above or below the equator. So in general, according to the tour guide, they do not cross the equator. According to wikipedia though, some whales from the southern hemisphere have been known to cross the equator. That is the exception though.
Click this link or one of the pictures above to see more pictures in the Moorea, French Polynesia Day 2 photo album. That album contains a video of the mother and calf.