The Sports Illustrated Swimsuit Issue includes 107 print ad pages this year, an 8% increase over the issue last year and the most since 2007, showing again that advertisers will pile into high-profile programming even if they aren't expanding their spending at other times.

Brands including Target, Mattel and Subway have created 15 custom campaigns for the issue, the 50th annual installation of the Swimsuit franchise, publisher Time Inc. said Tuesday as the issue was slated to reach newsstands.

Because of a higher ratio of editorial to ads than in some years, the issue's 260 overall pages make it the thickest since 1989, said Sports Illustrated Publisher Brendan Ripp.

Mattel's four-page spread and partial-run cover wrap has Barbie donning a version of the black-and-white striped bathing suit the doll wore when it was introduced in 1959. Both Barbie and the Swimsuit Issue have been accused of promoting unhealthy and unrealistic expectations for women's bodies, so the campaign -- preemptively themed "unapologetic" -- has drawn some criticism already.

Target also drew upon the swimsuit theme with ads for its limited-edition Black and Gold swimwear line, which it rolled out to mark the 50th anniversary issue. Despite the magazine's heavily male adience, Target wanted to advertise its swimwear collection in the "native-like" fashion that the Swimsuit Issue provides, according to Mr. Ripp.

The Swimsuit Issue's strong performance comes as magazines struggle to grow print ad pages amid growing competition from digital media. Print ad pages across all magazines declined 4.1% last year, according to the Publishers Information Bureau, with weeklies sustaining some of the sharpest losses.

Sports Illustrated's ad pages fell 6% in 2013.

Marketers turn out for Sports Illustrated's Swimsuit Issue partly because of its strong consumer demand, according to Mr. Ripp. "As the consumer continues to grow and be drawn to the franchise, so too do the advertisers," he said. "And they can be creative in the ways they choose to advertise."

The Swimsuit Issue generates large sales for Sports Illustrated, selling more than 800,000 copies on newsstands last year. By comparison, Sports Illustrated averaged just 68,132 newsstand sales per issue in the first half of last year.

Sports Illustrated also offered brands several digital and out-of-home extensions. The Swimsuit Issue's website features a spate of videos with pre-roll ads, and Target and Corona will each have a presence at the franchise's first party for consumers, a Miami event where swimsuit models and celebrity chefs will square off in volleyball.

Other creative Swimsuit Issue campaigns include work from Lexus, which sponsored the magazine's spine by directing readers to the page number of its ad, and Air New Zealand, which produced a four-minute safety video with current and former swimsuit models.