Three Side Seal Bag

Simple structure × material flexibility × the most widely used packaging style

Three side seal bag product image (illustrative)

The three side seal bag is one of the most common flexible packaging styles. As its name suggests, three sides are sealed during production, leaving one side open for filling. After sealing the final side, a flat pouch is formed. Made from two sheets of film, it offers a full front and back surface for printing.

Main Structure and Sealing Method
  • Typically made by overlaying two films and heat-sealing three sides—usually the left, right, and bottom—leaving the top open. After filling, the top is sealed to create a tight package. Because the bag relies solely on edge seals, it is best suited for small to medium sizes to maintain seal strength. Tear notches can be added for easy opening, and many three-side seal bags include zippers for repeated use.
Features and Advantages
  • The structure is simple and flat, making it easy and efficient to produce for small-portion packaging. With no center or side seam across the front and back, designs can be displayed clearly. Compared with four-side seal sachets, removing one seal offers slightly more internal volume. The style is versatile, allowing use of transparent film, aluminum foil composites, or paper-plastic laminates tailored to different needs.
Common Applications
  • Used for a wide range of items such as jerky, snacks, seasoning packets, instant sauce sachets, tea samples, pet treats, agricultural seeds, face masks, medical dressings, hardware, small electronics, and panel products. With optional hang holes, it's also popular for small hanging packages of coffee or cookies in supermarkets.
Thomson Value-Added Services
  • We offer various material structures, such as aluminum/PE, paper/plastic, and transparent/metallic layers, to meet barrier and appearance needs. Our patented registration technology enables high-quality printing on both sides. Zippers can be pre-applied inside the bag to combine the flat form with resealable convenience, and tear lines or serrated edges can be added for a better user experience.
Related Bag Recommendations
  • Stand Up Pouch: add a bottom gusset to stand upright.
  • Zipper Bag: adding a zipper to the three-side structure increases convenience.