Outstanding development opportunity near Daly City BART. 421 San Diego Ave is being offered in tandem with 425 San Diego Ave. Zoned R-1A and situated on oversized lots, this site presents versatile options for multi-unit residential development. Construct two duplex buildings, each with an attached or detached Accessory Dwelling Unit (ADU) resulting in a 6 unit development. Possible paths include constructing two single-family homes, each with an attached or detached ADU (4 units total), or utilizing SB9 to create two detached single-family homes with attached ADUs maximizing potential up to 8 units (buyer to verify). Additional highlights: - Level lots simplify construction - No permits required for tree removal - Gas service has been removed for easier demolition - Existing structure may qualify for financing Ideal for developers or investors seeking flexibility, location, and long-term potential in one of Daly City's most commuter-friendly pockets.