At any of the Anilao resorts, you can easily hire a boat that can take you out to sea for snorkeling. One trip is around P1500 but this is for a limited area. If you want to go island-hopping, you need to pay more.
Boats have lifevests.
If you are going to Anilao from the Cavite area, you can opt to take the route through Tagaytay and Lemery instead of the Star Highway. The view is a lot nicer - mountains, overlooking Taal Lake and I think it's a lot closer. Or it could just be that I was enjoying the drive and didn't notice the distance. :)