What are the best kid-friendly activities in San Diego?

[Peterkavinsky]

Planning a family trip soon—what are some fun and exciting things to do in San Diego with kids that will keep them entertained all day? Any personal favorites or must-visit spots you'd recommend?

 

[Louisegrant]

The best attractions are the San Diego Zoo, SeaWorld, LEGOLAND California, Balboa Park, and the beaches, tide pooling, and sandcastle building.