An in-seam pocket hides in a side seam. The whole technique is sewing the side seam and the pocket bag as one continuous line without catching the wrong layer.
The order.
One. Sew one pocket bag to the front seam allowance, right sides together, at the marked position. Sew the other to the back. Use a narrow seam allowance here, around 10 mm.
Two. Press each bag away from the garment, over the seam allowance. Understitch each one if the fabric is at all bulky — it keeps the bag from showing at the opening.
Three. Place front and back right sides together, matching the pocket bags.
Four. Sew the side seam from the top, stopping exactly at the top of the pocket opening. Pivot outwards, sew around the outside of the pocket bag, pivot back, and continue down the side seam. Backstitch at each pivot — those two points take all the strain.
Five. Clip the back seam allowance above and below the pocket so the bag can fold towards the front, and press.
Practical points. Reinforce the opening with a strip of interfacing or stay tape on the front seam allowance, especially on anything with give. Pockets that gape do so because the opening stretched.
Cut the pocket bags in lining or a lighter fabric if the garment fabric is heavy, but cut the section that shows at the opening in the garment fabric.
Check the pocket is deep enough and that the opening is where your hand actually goes, with the garment on.
Questions people actually ask
My pocket shows at the opening.
Understitch the bags away from the seam, and press firmly. Rolling the seam slightly to the inside helps too.
The pocket corners keep tearing.
Backstitch at both pivot points and reinforce the opening with stay tape. Those two corners carry every load the pocket takes.
Last reviewed 2026-08-11