The Thread Theory - Cosmos Trunks sewing pattern is designed for a form-fitting, comfortable boxer brief that moves with you. Featuring no center back seam, a reinforced inseam gusset, and a shaped front cup, these trunks fit like a second skin without rubbing or shifting. Short, athletic legs and a smooth elastic waistband create a streamlined silhouette suitable for wearing under slim-fit pants, gym shorts, or casual wear. Ideal for creating a functional, hand-made underwear wardrobe that combines comfort, style, and durability.
Key Features
Form-fitting boxer trunks for comfort and support
No center back seam for smooth, comfortable fit
Reinforced inseam gusset and shaped front cup to prevent rubbing or shifting
Short athletic legs with smooth elastic waistband for streamlined silhouette
Ideal for layering under pants, gym shorts, or casual wear
Part of the Alpine Outdoors Collection for hard-wearing, classic fit designs
Teaches precision sewing techniques for stretch fabrics
The Thread Theory Cosmos Trunks pattern is a form-fitting boxer brief with no center back seam, reinforced gusset, and shaped front cup. With short athletic legs and a smooth elastic waistband, this pattern allows sewists to create durable, comfortable, and stylish underwear for everyday or active wear.
