San Diego is a beautiful city with plenty of things to do and see. Here's an ideal itinerary for 4 days in San Diego:

Day 1:

• Start your day with a visit to the San Diego Zoo. It's one of the best zoos in the world and has a wide variety of animals to see.
• After the zoo, head to Balboa Park, which is right next door. Balboa Park is a beautiful park with plenty of museums, gardens, and other attractions to explore.
• In the evening, head to the Gaslamp Quarter for dinner. The Gaslamp Quarter is a historic district with plenty of restaurants, bars, and nightlife.

Day 2:

• Start your day with a visit to La Jolla Cove. It's a beautiful beach with crystal clear water and plenty of sea life to see.
• After the beach, head to the Birch Aquarium at Scripps. It's a great place to learn about marine life and conservation.
• In the evening, head to Old Town San Diego for dinner. Old Town is a historic district with plenty of Mexican restaurants and shops.

Day 3:

• Start your day with a visit to the USS Midway Museum. It's a great place to learn about the history of the US Navy and see some amazing aircraft.
• After the museum, head to Coronado Island. It's a beautiful island with a great beach and plenty of shops and restaurants.
• In the evening, head to Little Italy for dinner. Little Italy is a great neighborhood with plenty of Italian restaurants and shops.

Day 4:

• Start your day with a visit to the San Diego Museum of Art. It's a great place to see some amazing art from around the world.
• After the museum, head to the San Diego Botanic Garden. It's a beautiful garden with plenty of plants and flowers to see.
• In the evening, head to the Sunset Cliffs Natural Park for a beautiful sunset. It's a great place to relax and enjoy the view.

I hope this itinerary helps you plan your trip to San Diego!