Just one block from the water on the Balboa Peninsula, this newly rebuilt coastal residence delivers a rare combination of architectural restraint, elevated materials, and effortless indoor-outdoor living. Completed in 2025, the home spans approximately 3,577 square feet with four bedrooms, four full baths, and two powder rooms, designed for both everyday comfort and hosting at scale. A calm, gallery-like palette sets the tone throughout, with limewashed walls, wide-plank hardwood floors, and rich walnut detailing creating a sense of warmth and quiet sophistication. The main level is designed for entertaining, anchored by a striking living space with a backlit Crystallo stone fireplace, walnut paneling, and refined glass partitions that allow light to move freely throughout the home. The kitchen and adjoining pantry blend function and beauty with walnut cabinetry, Arabescato Gold honed marble surfaces, and a serious appliance lineup that supports real cooking and effortless gatherings, including a Gaggenau cooktop, Sub-Zero refrigeration, a Miele oven, dishwasher, and built-in coffee maker, plus a Wolf hood. Upstairs, an additional living and bar area extends the home's versatility with custom walnut cabinetry and Sub-Zero wine and beverage fridge, ideal for entertaining without bringing the whole party downstairs. Each bedroom suite is finished with spa-level baths wrapped in curated natural stone, custom vanities, and premium fixtures, while the primary suite stands apart as a true retreat with its own Crystallo stone fireplace, layered white oak detailing, and a serene bath finished in White Rhino and Thassos marble. Crowning the home is a rooftop deck built for year-round entertaining, with a full Thor outdoor kitchen featuring a pizza oven, sink, grill, and fridge, plus a gas firepit, integrated JBL speakers, and planters on a drip system. It's an ideal setting for sunset dinners, relaxed evenings, and hosting under the coastal sky. Additional highlights include a fully integrated smart-home system with Lutron RA3 keypads, a two-car garage, and a location that places the water and vibrant peninsula lifestyle just outside your door. Modern, refined, and thoughtfully executed, 503 J Street offers a turnkey opportunity for those seeking a coastal home that balances design, comfort, and proximity to the water, whether as a primary residence or an elevated Newport Beach retreat.