Welcome to 21 Marilyn Avenue, where Olde Florida charm meets one of the most desirable and affordable locations on Anastasia Island. Tucked away on a peaceful cul-de-sac beneath majestic live oaks and overlooking tranquil marsh views, this hidden gem is located in a neighborhood where homes rarely become available. Best of all, there are NO HOA fees and the property is located outside both the City of St. Augustine and City of St. Augustine Beach limits, allowing you to enjoy all the area's world-famous attractions without paying higher city taxes. If you've been searching for a home that embraces the Florida coastal lifestyle, this is it. Leave the car behind and walk or bike to the St. Augustine Amphitheatre, Saturday Farmers Market, Anastasia State Park, pristine Atlantic beaches, Lighthouse Park boat ramp, the St. Augustine Lighthouse & Maritime Museum, local coffee shops, restaurants and boutique shopping. Just minutes away, Historic Downtown St Augustine offers award-winning dining, waterfront attractions, galleries, festivals, and endless entertainment. Whether you enjoy boating, paddleboarding, kayaking, fishing, cycling, beach walks, concerts, or nature trails, adventure awaits just outside your door. Besides being a coveted neighborhood for families seeking the top elementary school zone of RB Hunt school, this welcoming neighborhood is known for its friendly atmosphere and cherished annual traditions, including a Fourth of July Fire Truck Parade, neighborhood block party, Halloween festivities, and Christmas in the Cul-de-Sacâcreating a true sense of community that's becoming increasingly rare. Built with solid concrete block construction and situated high and dry in Flood Zone X, this meticulously maintained home offers lasting quality and peace of mind. Move-in ready, it features beautifully refinished terrazzo floors, a 2025 HVAC system, 2021 roof, and EXTENSIVE 2026 IMPROVEMENTS, including a renovated master bathroom, updated electrical and plumbing, fresh interior and exterior paint, refinished terrazzo flooring, and sunroom windows and sliders that provide a view of the marsh beyond the back door. Home offers a complimentary 4 pt inspection. The flexible floor plan includes a built-in bookshelf and workspace in the third bedroom, making it ideal as a home office, guest room, hobby space, or library. A separate dining area provides multiple options for entertaining and everyday living. Step outside into your oversized backyard oasis, where peaceful marsh views and refreshing Intracoastal breezes create the perfect backdrop for relaxing or entertaining. With ample space for a custom pool, outdoor kitchen, garden, or future home expansion, the possibilities are endless. The large custom storage building with electricity offers incredible versatility as a workshop, art studio, fitness room, home office, or additional storage. One of this property's most exceptional and hard-to-find features is its picturesque marsh backdrop, where breathtaking views provide a front-row seat to abundant wildlife, including graceful shorebirds and visiting deer. Completing this private outdoor retreat are mature, fruit-bearing orange and fig trees, offering fresh fruit from your own backyard and enjoy a lifestyle of peaceful nature, beauty, and simple everyday pleasures rarely found in today's market. Whether you're searching for a primary residence where it is walking distance to the highly regarded St John's County school district RB Hunt elementary school, vacation home, second home, or investment property, opportunities like this are becoming increasingly rare. Offering an unbeatable combination of Anastasia Island location, walkability, bike-friendly coastal living, NO HOA, Flood Zone X, concrete block construction, a generous homesite, and exceptional updates, and an undeniable spectacular views, this property delivers remarkable value.