Fun for the Whole Family
San Francisco is a great city to visit with kids. There are a lot of activities and attractions to see that are fun for both parents and children.
Fisherman's Wharf and Alcatraz Island
Fisherman's Wharf: Although not a favorite among locals, Fisherman's Wharf is a major tourists stop. The Wax Museum and Ripley's Believe It or Not! are along the strip, as are Ghirardelli Square for a sweet chocolate treat and Boudin's famous Bakery and Museum. A bowl of clam chowder is a must as well.
Alcatraz Island: Ferries to Alcatraz launch from Fisherman's Wharf and would be fun for older children. Alcatraz, also known as The Rock, is the infamous federal penitentiary. Here's a link to the official Alcatraz booking site from the National Park Service. I recommend buying your tickets from the Park Service instead of from an affiliate so you don't get scammed. Advanced bookings are recommended, especially during the summer months. Tickets include: a ferry ride provided by Alcatraz Cruises and a cellhouse audio tour which is amazing. As you walk around the prison you will hear the stories told by actual inmates and prison guards. I recommend buying tickets weeks (if not months) in advance, especially in the summer.
Cable Car, Chinatown, and Union Square
Cable Car: There are three cable car routes: Powell/Hyde line, Powell/Mason line, and California line. Visiting San Francisco just wouldn't be complete without riding a cable car. If you plan correctly, it can bring you to a destination and replace a cab ride. Unfortunately, if you get off the cable car, you need to repay to get back on. The last time I rode one it was $5 a person one way. If you buy a Muni Passport you can get on and off and see the sites along the way.
The Powell-Hyde line will probably show you the most sites: Fisherman's Wharf, Lombard Street (The Crookedest Street in the World), Chinatown, Union Square, and Russian Hill.
Chinatown and Union Square: Chinatown is a great activity for kids and adults. Plus, you can easily walk a few blocks and you're in Union Square, the city center of great shopping.
Crissy Field and the Exploratorium
Crissy Field is a beautiful walk along the bay with views of the Golden Gate Bridge, Alcatraz and the City. It is near the Exploratorium, which is a must for elementary+ age children. It's a little too advanced for toddlers but great for older kids. I would go to the Exploratorium (closed on Mondays) and then walk to Crissy Field (north of Exploratorium and the Marina).
California Academy of Sciences: Steinhart Aquarium
The California Academy of Sciences is a must-see with your children, especially the Steinhart Aquarium. It is an amazing facility in Golden Gate Park. I highly recommend taking the whole family, as adults and children will love the exhibits.
Take Me Out to a San Francisco Giants Game
AT&T Park or the home of the San Francisco Giants is a great family activity! They have an amazing baseball park and on a sunny day, it's a great activity. There's a great slide and a lot of child activities in the park, and you get to see some of the best athletes in the game. Wear your orange and black and join in on the fun!
Bike the Golden Gate Bridge, Visit the Ferry Building and Sausalito
Bike the bridge: I haven't done this, but it looks like fun. Bike the Golden Gate Bridge to Sausalito and return to San Francisco by ferry to the Ferry Building. Blazing Saddles is the name of the company that offers this tour.
Ferry Building: The Ferry Building is now a high-end market in San Francisco. Open stalls offer a wide variety of foods, wine, and novelty items. If you don't want to bike the bridge, from here you can catch a ferry to Sausalito. A beautiful town on the east-side of the Bay known for its art galleries, shopping and waterfront dining. Here are the ferry schedules.
GoCar Golden Gate Park and Stow Lake
I think renting a GoCar would be really fun with kids, especially older ones. A GoCar is a GPS guided three-wheeled car with a narrated tour. Although expensive, I think this would be a memorable event. I would rent the car and cruise Golden Gate Park; if you plan it for a weekend, fewer cars will be on the road as the park closes a few streets to autos.
You can also GoCar Golden Gate Bridge, the Presidio and Ocean View, Ocean Beach, Inspiration Point, the Palace of Fine Arts, and Lombard Street. The safest bet is Golden Gate Park. The GoCars are difficult to see and can be dangerous on major SF streets. Here are some reviews from Yelp.
Take a Segway or Electric Bike Tour
If you have older kids, a Segway tour could be a great activity for your family! The guided tour incorporates fun and learning about the city. The Electric Tour Company provides guided tours for around 45 minutes for around $70. There are tours around the wharf, Alcatraz, Golden Gate Park as well as an advanced hills tour - which is perfect for San Francisco!