Diamond Bar, California - 5 Days Itinerary

• Day 1: Outdoor Adventure
  Start your trip with an adrenaline-filled day at the Hiking Trails of the Diamond Bar Community Nature Center. It's the perfect opportunity to enjoy a well-maintained trail and get great views. After lunch, take a scenic drive to the Frank G. Bonelli Regional Park, where you can fish, bike, or boat.
  
• Day 2: History and Art
  Take a morning tour of St. Denis Catholic Church, known for its beautiful stained glass window. Next, head to the famous Richards Mansion, an architectural wonder that is now a museum. In the afternoon, make your way to the Diamond Bar Historical Society Museum, which showcases local history and has a great collection of memorabilia.
  
• Day 3: Family Fun
  Today's all about fun for the whole family. Start with a visit to the Los Angeles County Arboretum & Botanic Garden, a 127-acre botanical garden featuring a zoo, a waterfall, and a historic mansion. In the afternoon, head over to the Big League Dreams Sports Park and enjoy batting cages, pitching tunnels and experience 5 replica fields of MLB parks.
  
• Day 4: Sweet Delights
  Treat yourself with pastries and coffee at the Paris Baguette Bakery & Café. Then, visit the Galster Wilderness Park featuring a strenuous hike top by a tower with breathtaking views of the city. In the afternoon, delight your sweet tooth with a stop at the Churro Stix and enjoy hot, freshly made churros.
  
• Day 5: Shopping Spree
  End your trip with a shopping spree at the Diamond Bar Plaza, it has shops from popular brands like Old Navy, Banana Republic, and Bath & Body Works. At night, dine in at JJ’s Crab, favoring their dungeness crabs and boils.
  

Time and Cost Estimates

• Hiking Trails of the Diamond Bar Community Nature Center (2 hours, free)
• Frank G. Bonelli Regional Park(4 hours, $10 for parking)
• St. Denis Catholic Church (1 hour, free)
• Richards Mansion Tour (1 hour, $8)
• Diamond Bar Historical Society Museum (2 hours, $5)
• Los Angeles County Arboretum & Botanic Garden (4 hours, $15)
• Big League Dreams Sports Park(3 hours, $20 for a batting cage token)
• Paris Baguette Bakery & Cafe (1 hour, $10)
• Galster Wilderness Park(2 hours, free)
• Churro Stix (1 hour, $5)
• Diamond Bar Plaza shopping (3 hours, varies)
• JJ's Crab (1.5 hours, $50)

Transportation

Considering the spread-out nature of Diamond Bar, travel by car is highly recommended. You can rent a car at the nearest airport, LA/Ontario International Airport, for around $35 per day. The average travel time between attractions is about 15 to 20 minutes. Lyft and Uber are available options.

Useful Tips

If you have an extra day, consider exploring the Brea Mall, there are plenty of uncrowded shops. If time is tight, you might skip either the Diamond Bar Historical Society Museum or the Richards Mansion. Don't forget to bring sunscreen and insect repellent for outdoor activities.