From A Wiki of Ice and Fire
West of the Summer Sea is the Sunset Sea. Just east of Dorne, the Summer Sea is separated from the narrow sea to the north by the island chain known as the Stepstones. South of Westeros and the Stepstones are the Summer Islands. East of the Summer Islands are Naath, Sothoryos, and the Basilisk Isles. North of those locations are the Valyrian peninsula, the Gulf of Grief, and Slaver's Bay. The eastern Summer Sea meets the Jade Sea at the Straits of Qarth, also known as the Jade Gates, and the Cinnamon Straits.