Snorkel-Hike Kealakekua Bay
Kealakekua Bay offers some of the best snorkeling in the entire state. The place that you'll want to snorkel from is by the Cook Monument. However, to get there you'll either have to rent a kayak or hike in. To hike to the monument, take the trail found, according to the guidebook Hawaii the Big Island Revealed, at the intersection between Highway 11 and Napoopoo Road. The trail is two miles each way and descends 1,300 feet, so it's a good idea to bring plenty of water and wear a good pair of hiking shoes. At the monument you'll find excellent visibility which, according to the Hawaii Division of Aquatic Resources, can range from 5 to 120 feet. Keep an eye out for trigger fish, dolphins and turtles.
Kealakekua Bay State Historical Park
Puuhonoa Road
Kealakekua, HI 96750
http://www.hawaiistateparks.org/parks/hawaii/kealakekua.cfm
Spend the Day at Volcanoes National Park
Volcanoes National Park is an excellent place to visit with numerous trails. Among them is Devastation Trail, which takes you through a forest. You can see where the lava destroyed some of the forest. Be prepared to spend all day there, or come back in the evening, which is the best time to see the orange glow from the lava flow. Check the U.S. Geological Survey site to get the most up to date information on where the lava is flowing. Bring a good flashlight because you'll be returning in the dark.
Volcanoes National Park
1 Crater Rim Drive
Hawaii National Park, HI 96718
(808) 985-6000
http://www.nps.gov/havo/index.htm
Snorkel at Champagne Pond
Champagne Pond combines an interest in snorkeling with volcanic activity. The pond is an inlet carved from lava and protected from the open water, where you can snorkel and actually see where the temperature changes in the water. Champagne Pond is warm, usually around 90 degrees. The fresh water in the pond is heated by the volcano. Look for turtles which congregate in the pond's warm waters.
Champagne Pond
14-5000 Laimana Ave
Pahoa, HI 96778