Bike Seatpost Bag
with Waterproof
Fabric 12L Adsports


Availability: In stock

SKU: NB12LWP Categories: ,

These bike seatpost bag is perfect if you don’t have a pannier rack. They conveniently attach to your bike’s seat post for quick and easy installation. Perfect for bikepacking when using with one of our frame bags and front handlebar bags.

Similar to our front barrel bags they close using two buckles which connect to extendable straps. This enables the bag to be rolled up and down to adjust the size then sealed like a dry bag.

12L Seatpost Bag straps and buckles

If you need to use the full 12 liter capacity of the rear bike bag then the bag can be sealed using the zipper. The zip is a high quality zipper which using flashing to reduced the amount of water which leaks through the zipper.

Zipper with flashing

For extra storage capacity there is an elastic net on tp of the bag. This net can be used to store frequently used items such as your water bottle. Alternatively this storage area can be used to dry wet clothes such as raincoats. Please note, the pictured water bottle is not included.

Elastic net for extra storage on bike seatpost bag adsports

As well as having a place to pack your gear into, the bag will increase your visibility while riding in the dark. The logo and nets buckles are reflective adding side reflectors to your bicycle. There is also an additional reflector on the back of the bag which is essential if you have to remove your existing reflector.

adsports bike bag reflective tags NB12LWP

This bag features 2 layers of protection. The outside layer is made from Polyester fabric which is the first layer of protection, this layer sheets off the majority of water. Inside of the rear bike bag is lined with TPU which adds the final layer of protection blocking any water which manages to leak through the layer of Polyester.

Bike Seatpost Bag Specifications (NB12LWP)

  • Model Number: NB12LWP.
  • Brand: Adsports.
  • Bag Material:: Polyester + TPU.
  • Maximum storage capacity: 12 Liters.
  • Maximum loading: 8 kg.
  • Net Weight: 457 grams +/- 5 %


For added protection we recommend all sensitive items such as electronic devices be stored inside another bag with this bag. Over time the bag could lose it’s waterproofness so better to err on the side of caution.

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