The On Trail 20L Unisex Pack is a high-performance technical backpack engineered to deliver stability and organisation on the most demanding terrain. Designed with a form-fitting vest-style harness, this pack eliminates unwanted bounce during high-intensity movement, making it an essential companion for trail running and fast-packing. The 20-litre volume provides ample room for all your mountain essentials, while the roll-top closure allows you to compress or expand the load depending on your gear requirements. To ensure your belongings stay dry in unpredictable weather, the water-repellent main compartment is constructed with taped seams to shield against the elements. Comfort is prioritised through a structured, suspended back panel that promotes airflow and support, paired with adjustable straps that allow for a completely customised and secure fit.

Key Features:

  • 20-litre volume: Offers a generous capacity (15L internal plus 5L external) for extra layers, nutrition, and emergency kits.
  • Form-fitting vest harness: Provides a snug, ergonomic fit that distributes weight evenly across the torso for maximum stability.
  • Water-repellent main compartment: Features to keep your core gear protected from rain and moisture.
  • Roll-top closure: Ensures a secure seal and allows for easy volume adjustment based on your current load.
  • Hydration-ready: Features two compact front pockets for soft flasks (not included).
  • Integrated pockets: Includes a front zippered pocket for your phone, external stretch pockets made of sturdy ultra-high molecular weight polyethylene (UHMWPE) yarn, and front slip pockets for quick-access items while on the move.
  • Breathable back panel: A suspended, framed design that offers superior ventilation and structural support during long efforts.
  • Adjustable straps: Fully customisable shoulder and torso straps ensure the pack remains locked in place regardless of body type.
  • Bungee cords: Includes dedicated attachment points and elastic cords to securely stow trekking poles or additional external gear.

The main compartment is water-repellent with taped seams designed keep gear dry in light to moderate rain.

The On Trail 20L has no dedicated sleeve for a hydration bladder but it has two compact front pockets that fit soft flasks (not included).

Brand : On Running

SKU: ONRN-trailpk20L-u

Model # : trailpk20L-u

Gender : Unisex

Pack Volume : 20-39L

Weight : 785g

Volume : 20L Total (15L Internal | 5L External)

Fabrics : 100% Recycled Polyamide (Main) | 100% Recycled Polyester (Back Panel) | UHMWPE (External Pockets)

Free shipping on orders over $100 to Australia & NZ*
Shipping on small orders (under $100) only $9.95
Express shipping to Australia & NZ only $15

Standard Shipping (AU/NZ) – FREE on orders over $100 and $9.95 on orders under $100. Orders are dispatched within 1 business day. Click here for shipping delivery times

Select ‘Standard Shipping – Auspost Only’ if you would prefer your parcel is sent with Auspost. Otherwise it will be shipped with any of our available carriers. Auspost Only shipping is not available on some very heavy/bulky orders.

Express Shipping (AU/NZ) – Need it faster? Express Shipping is available for $15. Express Shipping is not available on heavy/bulky orders. Orders placed before midday on business days are usually dispatched same day (otherwise within 1 business day). Delivery times in the table below.

Click and Collect – Shop online and collect in our Milton, Brisbane store, free for all orders. Orders are usually ready within 2 hours (during opening hours). Click here for address and opening hours.

Terms and conditions apply, click here for a full overview of our shipping policies

Manufacturing defects covered, replaced or repaired if soon after purchase.

  • If you have selected the wrong product/size for you, or want to exchange/return for any reason except for warranty or our error, this is referred to as a 'change of mind' return.
  • Not all products are eligible for change of mind returns (click here for excluded products). Final Clearance products are not eligible for change of mind returns.
  • Once you submit a Return Request, we will provide return instructions via email (along with a prepaid return label if applicable). Please wait to receive this before returning any items (Try 2 Anything excluded)
  • Change of mind returns can be resolved by your choice of exchange, full store credit, or a refund. Refunds are subject to a $19.95 admin fee.

For a full overview of our returns and warranty policies, see Returns and Warranties

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