San Diego Excellent Adventures, San Diego

Disguised in wetsuits, flippers, and diving masks, humans almost seem indistinguishable from the scores of aquatic life that thrive among the San Diego coastline. In the water, curious sea lions tug playfully at divers' fins, and thick stalks of kelp wave like Queen Elizabeth telling the gathered crowd to go home already. With access to five separate sites in which to see such wonders, the guides at San Diego Excellent Adventures tailor their adventures—whether snorkeling, diving, or paddling—around the experience level of each tour group, ensuring an easy assimilation to undersea life.

During guided dives along La Jolla Shores, swimmers peer in on frolicking creatures such as lobsters, octopuses, and leopard sharks, and standup paddleboards grant access to Mission Bay's shoreline views previously seen only by terribly lost Venetian gondoliers. Currently the largest manmade bay in the country, Mission is known for its calm waters suited to beginners just learning to explore the ocean.