even if you're a good swimmer, it is advised that you wear a life vest when you take to the water and swim alongside the whalesharks. even if you're a seasoned swimmer, do not underestimate the excitement you'll experience when you see these gigantic creatures for the first time.
from the moment the spotter sees one, you'll only have a few moments to dive into the bay from the boat and rush to the spot. i can tell you from experience that during this mad rush, you'll surely swallow water and it's very possible to lose your bearings or even suffer a cramp.
although water in the bay is usually calm, a life vest will ensure that you don't sink or get into any trouble during your swim.
don't worry that a life vest might impede you from going underwater to see them, the whalesharks usually swim less 10 feet from the surface. this means snorkeling just below the surface will be enough for anyone to get a great view.
If possible, try to lessen your breakfast intake to avoid being seasick at the whale watching trip. You'll get nauseated easily causing you to become seasick and eventually you'll be puking at sea.
For others who get seasick easily, best advice is to take meds before going into the water.
I heard that one boat the day before us went back only after 45 minutes because one of its passengers became seasick.
The sea tend to be rough at times so it's best to practice swimming before going to Donsol. A relatively fair swimming skill is advised if you want to maximize the full experience. If you're a slow swimmer, you might get carried by the waves and miss your whale shark encounter.
Don't worry, you won't drown btw. There are life vests available in the boat.
There were no available vans to Legaspi by the time we were ready to leave Donsol. The locals said that the drivers joined in the celebration. A local offered us P1500 van rental to Legaspi but it was too expensive for us.
The town fiesta was May 17-18.
Best alternative is to ride a jeep to Daraga, Albay. Then take a jeep again to Legaspi.
BRING YOUR OWN SNORKELS!! There is a snorkel rental place in Donsol, but they do not sanitize it in any way. If you don't care about using a snorkel that has been used by dozens of people before you and has never been cleaned (except by the saltwater I guess), then it shouldn't be an issue. If you do decide to rent one, BARGAIN with the people. I got my snorkel and fins down to 100 pesos.