Kayak to a waterfall.
Snorkeling maui vs kauai. Go for the Big Island Manta Ray snorkel since it is unique and just go snorkel off the beaches on both Maui and Big Island. Correct me if Im wrong. Kauai is primarily an algae reef and that is what drives the ecology.
Kauai offers great views of coral reefs and is home to a rainforest. Kauai offers many attractions but not even one quite as famous as Mauis Road to Hana. Kauai is much more limited.
Kauai is called the Garden Isle since most of the island consists of mountains and rainforests which gives the island a lush wet climate. Note that some of the treks are suited to experienced hikers such as the Kalalau Trail a 22-mile minimum two-day trek along the Na Pali Coast but there are still some places where newbies can set off and see staggering sights. One particularity of this island are the black sand beaches which are made of ground lava rock.
Maui is a snorkeling hotspot known as one of the best spots to snorkel in the entire world. Its why snorkeling with friendly sea turtles is all but guaranteed in Maui. Kauais attractions are a bit.
Snorkeling is good on Kauai but Maui has some of the best places to snorkel in Hawaii. Kauai doesnt have bad snorkeling. While both islands have good snorkeling Maui has more top-notch sites and more are easily accessible from the beach.
Kahekeli beach south of Honokowai and Kapalua north are good on the west side Maui. The best snorkeling locations are a half-mile swim from shore. Inverts and Turtles are slightly more plentiful in my opinion but you would never know the difference.