Welcome to 10540 Costello Dr, a stunning POOL HOME in the prestigious Barcelona community of upper Tustin Ranch. Situated on an ultra-rare 9,600 sq ft corner lot, the second biggest lot in Barcelona, the home offers space as well as privacy. Boasting 4 bedrooms plus a Loft, 3 full bathrooms, and 2,754 square feet of living space, the home provides ample space for comfortable living. Upon entry, you'll be stunned by the stunning 18' ceilings and natural light that floods into the Living and Dining Rooms. The open-concept floor plan also features a desirable downstairs bedroom, perfect for guests, multigenerational living, or an office, along with a full bathroom and dedicated laundry room for added convenience. A comfortable Family Room offers even more usable living space and boasts a cozy fireplace ideal for relaxation and gatherings. The gourmet Kitchen is a chef's dream, equipped with a walk-in pantry, large center island w/wine fridge, granite counters, stainless steel appliances, stone backsplash, and a charming breakfast nook. Outside, the entertainer's backyard is undoubtedly the envy of the neighborhood, featuring a sparkling pool and spa, covered patio, grassy lawn, and built-in BBQ, perfect for outdoor gatherings and enjoying the lifestyle only Southern California can offer. Upstairs, the luxurious Primary Suite boasts a sitting area, ensuite bathroom with separate shower and soaking tub, dual vanities, and a spacious walk-in closet. Two additional bedrooms upstairs share a Jack & Jill bathroom, while the Loft provides a versatile space for work or play. Other convenient features and luxurious upgrades include a 3-car garage + spacious driveway, plantation shutters, and new LVP flooring. Enjoy the convenience of low HOA fees and no Mello-Roos! 10540 Costello Dr is walking distance to Pioneer Road Park, Peters Canyon Elementary, Pioneer Middle School, and a short drive to shopping and dining options at the Market Place. With easy access to freeways and toll roads, as well as nearby parks like Peters Canyon, Tustin Sports Park and Irvine Regional, this home truly embodies the best of upper Tustin Ranch living. Spacious pool homes with features like this don't last long... Call to schedule a tour today!