Sitting in the back seat of a friend’s Jeep, No Doubt’s Tragic Kingdom blaring from the speakers, shoulders and thighs all pink from the sun -- that’s what summer is all about. It’s nostalgic, frivolous, and so damn hot -- precisely why square-cut shorts are the choice for swimwear this year.

They are retro (don’t limit yourself to basic black and navy; go for strong color and prints) and yet very current. Bikinis aren’t for everyone, but these shapes are sexy while leaving a little to the imagination. Square-cuts are youthful but not juvenile -- and very fresh indeed.

Navy and white striped square-cut trunks by Diesel. White nylon square-cut trunks by DSquared2.