They are located on the lava flows south of Wailea. If you are a Kayaker this is a really good way to view the south coast and Kanaio area with your snorkel gear. Visit Pacific Kayaks in Kihei for all your paddeling needs. Easier access can be found at Olowalu at the mile 14 marker about 6 miles south of Lahaina or Black Rock at the Sheraton Maui Hotel in Kaanapali. Here you will see Maui's famous green sea turtles.
Access is from a sandy beach and water is safe and shallow.
For non-swimmers and kids Olowalu is perfect. Black Rock incidentally makes an excellent night dive for scuba divers. Your other option is to get on a snorkel boat to Lana'i or Molokini. Try a rafting adventure to Lana'i which includes a wild dolphin search and a couple of hours of snorkeling in a half day morning trip. Molokini snorkeling is in the protected semi-circle of this extinct volcano which has it's northwest side eroded away from wave action.