If you're up for hitting three parks, Costco.com has a San Diego 3-for-1 pass for $99.99 for adults and $79.99 for a child (ages 3-9). The three attractions are Sea World, San Diego Zoo and San Diego Wild Animal Park.
Programs: DL PM; US Silver;Mariott+SPG+Hyatt Gold; Hertz 5*; National Car Emerald; Avis Preferred
Some free things to do include visiting the Seals @La Jolla cove(This is more of an evening activity), Sunset Cliffs, Mt Soledad, parking @ Mission Bay to watch the Sea World fireworks... i'm sure others have more suggestions
Location: San Diego, CA , 4.2MM+ AA Platinum, Hilton Diamond, Starwood Gold
I am confused-
Your post is dated June 22nd but your travel dates are 6/12-6/15?
How old is the child?
Re: "The beach thing" June is the worst month to come to san Diego - May Grey is followed by June Gloom and we usually do not see the sun until well after noon, if at all. Last night it was too cold to eat outside and we had to go inside after drinks at 5 PM. Not to be aspoiler, but last July 4th we couldn't even see the fireworks due to the low marine layer (I live at the beach).
If you are coming before July 4th, the County Fair is on and is a lot of fun.
The Cabrillo Monument is one of my favorite places. The model train museum in Balboa park is often overlooked and is fun.
The Corvette Diner in Liberty Station is always a big hit with kids (of all ages -but having a kid is a great reason to go there.)
Adjacent to Legoland (which has added a water park and aquarium - and has great ticket deals at the adjacent Costco) is the U Pick strawberry fields that are fun.
The absolute best beach in San Diego is in front of the Hotel Del Coronado. We actually drive and pay to park there so we can have easy access. Their beachfront restaurants are reasonable and convenient.
The San Diego Harbor excursion is actually worthwhile and reasonable priced. The one hour one is just long enough.
The USS Midway is interesting and worthwhile. If you like tall ships, the Martitime Museum is fun and the Star of India is well maintained.