The whale sharks of Donsol were just filmed in 1998 by a team of divers and it is only since then that they have been attracting tourists. Today there is no diving allowed in the area where the whale sharks congregate only snorkeling thanks to the protection of the World Wildlife Fund. This allows the sharks a bit of privacy if they get upset with tourists swimming a few feet away from them. They simply dive deep and you are left swimming all alone. With this said though, you will probably get many chances to swim the massive fish if you go at the right time of year, but there is no grantee. When I was there, I saw 17 different whale sharks on the first day and 10 the next. However, another tourist on another boat saw none during the same two days.
The first thing to do is get a good boat crew at the Department of Tourism. Get a boat driver and a spotter that is experienced enough to get you perpendicular to the shark so that it is swimming towards the boat when you jump out. If you do this, you will only have to tread water and the sharks will come right to you. If your driver just pulls up along side of the sharks, you will have to do a lot of extra swimming to catch up. On the rare occasion, the driver will only go behind the shark and any chance of catching up is very slim.
Typically, the sharks hang out alone on the surface feeding on plankton and don’t seem to mind humans only a few feet away. While you are not allowed to touch them, you can take all the pictures you want. One problem for viewing is that the whale sharks stay close to shore, feeding at the river mouth, and this silt makes the water very murky. Once the whale sharks dive deeper then 20 feet, it becomes a challenge to see them. So be prepared to only get a few minutes with some if they do not like you near. Some, though, will let you swim with them as long as you want.
This is an experience that is not to be missed. There are only two other places in the world where the whale sharks come together in such numbers: the Galapagos Islands and Australia.