Irvine-based Billabong USA, a designer and retailer of clothes inspired by surfing, skateboarding and snowboarding, is buying San Clemente’s Swell.com, an online clothes seller.

Terms of the deal weren’t disclosed.

“The internet plays a significant role in the recreational habits of the youth market so it is important for our group to ensure we provide them with a premium brand experience when shopping online,” said Paul Naude, president of Billabong USA.

Swell, which started in 1999, sells surf- and skate-inspired clothes for guys and females as well as surfboards, skateboards, wetsuits and other gear.

The site sells clothes from several Orange County apparel companies, including Billabong, Huntington Beach-based Quiksilver Inc. and Costa Mesa-based Volcom Inc.

Nicholas Nathanson, a former e-commerce analyst at Salomon Smith Barney and Jeffrey A. Berg, a finance and new media executive, started Swell.com, according to a report in trade publication Apparel News.

The acquisition is the latest in a series for Billabong, a unit of Australia’s Billabong International Ltd. that makes up half of its parent company’s $1 billion in yearly sales.

Last year, Billabong acquired Oregon accessory maker DaKine and San Diego skateboard maker Sector 9.

The company made a big move into retail in 2004 when it bought Hawaii’s Honolua Surf Co. stores and Southern California’s Beach Access, a chain of stores now called BeachWorks that sells Billabong brands and others.