Long Beach is a beautiful coastal city in Southern California that offers a variety of activities and attractions. Here's an ideal itinerary for 3 days in Long Beach:

Day 1:

• Start your day with a visit to the Aquarium of the Pacific, which is home to over 11,000 animals from the Pacific Ocean. You can spend a few hours here exploring the exhibits and learning about marine life.
• After the aquarium, head to Shoreline Village, a waterfront shopping and dining destination. You can grab lunch at one of the many restaurants here and enjoy the views of the marina.
• In the afternoon, take a stroll along the beach at Long Beach Waterfront. This is a great place to relax and soak up some sun.
• End your day with a visit to the Queen Mary, a historic ocean liner that has been converted into a hotel and museum. You can take a tour of the ship and learn about its fascinating history.

Day 2:

• Start your day with a visit to the Museum of Latin American Art, which features contemporary art from Latin America and the United States.
• After the museum, head to the Long Beach Museum of Art, which is located on a bluff overlooking the ocean. The museum features a collection of modern and contemporary art.
• For lunch, head to Retro Row, a neighborhood filled with vintage shops, cafes, and restaurants. You can grab a bite to eat at one of the many eateries here.
• In the afternoon, take a bike ride along the beach path. You can rent bikes at several locations along the beach and enjoy the scenic views.
• End your day with a visit to the Pike Outlets, a shopping and entertainment complex that features a variety of stores and restaurants.

Day 3:

• Start your day with a visit to the Rancho Los Alamitos Historic Ranch and Gardens, which is a restored ranch house and gardens that dates back to the 1800s. You can take a tour of the property and learn about its history.
• After the ranch, head to the Naples Canals, which are a series of canals and bridges that were modeled after Venice, Italy. You can take a gondola ride through the canals and enjoy the scenery.
• For lunch, head to the East Village Arts District, which is a neighborhood filled with art galleries, cafes, and restaurants. You can grab a bite to eat at one of the many eateries here.
• In the afternoon, take a hike in El Dorado Nature Center, which is a 105-acre nature preserve that features hiking trails and wildlife viewing opportunities.
• End your day with a visit to the Long Beach Museum of History, which features exhibits on the city's history and culture.

I hope this itinerary helps you plan your trip to Long Beach!