From August 11 to 20, 1950, Seafair, including the Aqua Follies on Green Lake, is held for the first time in King County. Seafair is a festival of boat parades, a swimming meet, a badminton tournament, a Kiddies' Doll and Pet Parade, dancing, musicals, bicycle races, tugs of war, a baby beauty contest, Scottish Highland games, national waterski championships, a Hole-in-one Golf Tournament, a steamboat race, a lifeboat race, a "Huckleberry Finn fishing rodeo," the world's largest clambake, a bonfire using an old boat as fuel, and a grand finale of fireworks. As part of Seafair, the International District holds an elaborate "International Carnival" involving a "a huge lion-headed beast engaged in mock combat," there is a Filipino bamboo dance, and the famous Bon Odori. Last but not least, on August 11, 1950, Seafair's opening day, the Aqua Theatre on Seattle's Green Lake holds its first show.
A centerpiece of the first Seafair was the Aqua Follies with a cast of 125 performing on the south shore of Green Lake in Seattle. The Aquadears and Aquadivers, performed a "swimusical review" for the first time outside of St. Paul, Minnesota. They performed water ballet, and trick and comic dives from two four-story-high towers built as part of the Aqua Theatre. There was also a stage show and singing.