It can only be obtained by connecting to the Gamecube game Harvest Moon: A Wonderful Life via the Harvest Goddess. To initiate a connection, you must throw a gift into the Harvest Goddess's pond, and she will ask you if you would like to connect. You must connect 42 times to receive the Seaside Cottage as a gift.
The house features blue-and-white themed furnishings, including a clock, bed, calendar and diary. A large window overlooking presumably the ocean replaces the television.
Like all the other additional homes aside from your farmhouse, the Seaside Cottage is not expandable or upgradable. Furthermore, your husband/wife and/or child will not move here with you.