Beach volleyball, or sand volleyball, is an Olympic team sport played by two teams of two players on a sand court divided by a net.

As in indoor volleyball, the object of the game is to send the ball over the net in order to ground it on the opponent's court, and to prevent the same effort by the opponent. A team is allowed up to three touches to return the ball. The ball is put in play with a service—a hit by the server from behind the rear court boundary over the net to the opponents. The rally continues until the ball is grounded on the playing court, goes "out", or is not returned properly.

The team winning a rally scores a point (Rally Point System), and serves to start the following rally. The four players serve in the same sequence throughout the match, changing server each time a rally is won by the receiving team.

Originating in the US states of California (Southern California) and Hawaii, beach volleyball has achieved worldwide popularity.

In 1920, new jetties in Santa Monica, California created a large sandy area for public enjoyment, planting the seed for beach volleyball development in that region. The first permanent nets began to appear, and people soon began playing recreational games on public parts of the beach and in private beach clubs. Eleven such beach clubs appeared in the Santa Monica area, beginning in late 1922. The first inter-club competitions were staged in 1924.

Christopher St. John ("Sinjin") Smith (born May 7, 1957 in Santa Monica, California) is a professional beach volleyball player. He won one U.S. championship and two World championships with Randy Stoklos.

He began to compete as a professional in the two man beach volleyball tournaments of Southern California at age fifteen. In 1977 he won his first tournament, teaming with "Stormin" Mike Normand. He went to college at UCLA, where he played volleyball as a setter under head coach Al Scates. The UCLA Bruins reached the finals in 1978 before losing to Pepperdine. In 1979 the Bruins defeated cross town rival USC to win the National Championship. Smith received All American honors both years. In the early 1980s he made a successful beach team pairing with former UCLA teammate Karch Kiraly. The partnership split up as Karch came to focus on the National Olympic Team. Smith moved on to partner with Randy Stoklos, and the two became the most dominant pair in men's beach volleyball. Smith was the first player to reach 100 career open tournament wins. He was a primary force behind the growth of beach volleyball as a sport, and the development of the Association of Volleyball Professionals, which formalized the sport as a professional athletic competition. In the late 1980s and early 1990s "Smith and Stoklos" were the kings of the beach.