Say the word "snorkeling" and images of warm, azure seas and schools of eye-popping, multi-colored fish instantly spring to mind. But try that with "Pacific Ocean" and chances are you get cold, dark, murky water instead. And that's more or less the ugly truth, with one grand exception being San Diego's magnificent La Jolla Underwater Park and Ecological Reserve. The 6,000-acre marine refuge, a nook on the Pacific coastline dubbed America's Riviera, may still be on the chilly side (even in summer, when it fails to reach 65 degrees), but the 30-foot visibility in its waters and variety of sea life more than make up for it. The SoCal sea here teems with life around the two reefs (and seven caves): Garibaldi (the orange California state fish), eels, guitarfish, sheephead, rays, leopard sharks (and sometimes some of their larger, white relatives), large black sea bass, agile dolphins, and a healthy (and noisy) community of seals to boot.

San Diego Bike and Kayak tours offers a few ways of getting close to the ocean action, but we prefer the "kayak and snorkel" package. The 2.5-hour tour includes a basic plastic sit-on-top sea kayak (which is plenty stable for beginners) and all your snorkeling gear. A guide takes you through the kelp forest – giant, 90-foot-long strands of spinachy, fast-growing seaweed – on the way to 7 Caves, spotting seals and other wildlife along the way. It's not adrenaline-spiking adventure travel, but it's an enlightening glimpse into the wildlife-dense habitat, and pretty unique for the West Coast in general. And it's just a plain relaxing, fun way to spend a day that's appropriate for all ages. [From $52; sandiegobikeandkayaktours.com]