H2Oasis Indoor Waterpark is a 56,000 square foot (5,200 m²) Indoor Waterpark located in Anchorage, Alaska just east of the Seward Highway at 1520 O'Malley Road. It opened in 2003 and is the fifth largest indoor waterpark in the United States. Only Wilderness Hotel & Golf Resort, Kalahari Resort and Convention Center, Water Park of America, Chula Vista Resort's Lost Rios and Great Wolf Lodge Wisconsin Dells are larger.