Hyatt Regency Lake Washington at Seattleâs Southport is a tranquil sanctuary, sharing the quiet waters along the south shores of Lake Washington and adjacent Gene Coulon Memorial Beach Park. Waterfront vistas of the lake, Olympic mountains and Seattleâs skyline grace our myriad of elegant spaces. Windows framing the views create a near nature feel for your Seattle wedding inside our 14,000 square foot Grand Ballroom or 5,000 square foot Lake Washington Ballroom. Outdoor terraces adorn both spaces and create that perfect marriage of nature and class.