There's a lot to do in and around Kona...
Swimming with dolphins can be an indescribable experience. Goosebumps. There are different possibilities to see dolphins. You can book a dolphin excursion with a tour company or take your chances at one of the places along the coast where you can swim with pods of dolphins from the shore.
Manta Ray Night Dive or Snorkel
"Personally, if you are only going to pay to do one activity while on the Big Island, I would recommend the mantas. Its a really awesome experience to see these sea creatures up close!" Swimming with manta rays is an experience that cant be found very many places in the world. Most companies offer both snorkeling and dive trips. Manta excursions take place year round however, during the winter months when the waters are a bit rougher the mantas may not want to come as close to the surface or may not come out at all. Most companies have a manta guarantee.
Between November and April/May the humpback whales are hanging out in Hawaii taking advantage of the warmer water temperatures and lack of predators. You can see the whales from shore but if you want a close up look and a chance to take National Geographic worthy pictures consider a whale watching boat tour. It is an amazing site to see whales breaching and tail flapping up close!
Beaches and Snorkelling
Snorkeling on the Big Island is the best in the state. Two of the best and most easily accessible snorkel spots are within 30 minutes drive of My Hawaii Hostel. Kahalu'u Beach Park, just 3 miles from the hostel, and is a great spot for snorkeling as well as surfing. Two Steps and Kealakekua Bay are said to be the best snorkel spots on the Island where you also have the possibility to see dolphins.
Within a hour drive of Kona you will also find numerous beaches ideal for hanging out, swimming, and surfing. Just a few are Magic Sands, Kua Bay, Makalawena, and Beach 69. This list is by no means comprehensive. Ask around; everyone has their favorite beach!
Hawaii is the birthplace of surfing and attracts surfers of all levels from around the world. So whether you're new to the ocean and want to try surfing or are experienced and want to challenge yourself, the Big Island has a surf spot just for you. There are a number of surf shops and individuals that rent gear, have lessons, and can provide recommendations as to good spots so just as the staff for some recommendations. Get out there and catch some waves!
There are over 20 Farmer's Markets around the Big Island. So as you travel around, support local artisans by purchasing locally produced food and souvenirs! Check out this map for locations and times.