On
Core 5" Short
The On Core 5" Short is a lightweight running short constructed from stretch recycled polyester, with a built-in microfibre brief and an elastic waistband featuring an adjustable inner drawstring. It offers three pockets (including slant front pockets and a rear zip pocket) for carrying essentials, and has a 5-inch (12.75 cm) inseam with a reflective logo. These shorts are intended for running and athletic use, providing a secure fit and convenient storage.
- Material
- Recycled polyester and microfibre
- Style
- performance, sporty, lightweight
- Category
- Sporting Goods > Athletics > Track & Field
Specifications
Ultra-light running shorts with built-in brief and three pockets.
Ultra-light, stretch fabric made from recycled polyester, built-in microfibre brief, elastic waist with adjustable drawstring, slant pockets and zip pocket, reflective logo.
- Material
- Recycled polyester and microfibre
- Secondary
- polyester
- Style
- performance, sporty, lightweight
- Occasion
- workout, sports-event
- Gender
- male
- Age Group
- adult
- Condition
- new
- Category
- Sporting Goods > Athletics > Track & Field
Additional Attributes
- ultra-light
- built-in brief
- stretch fabric
- recycled polyester
- elastic waist
- adjustable drawstring
- three pockets
- slant pockets
- zip pocket
- reflective logo
- 5-inch inseam
Product Insights
On's Core 5" Short is a relaxed-fit running short that prioritizes chafe prevention and comfort through an inner brief with hydrophobic microfiber and side slits that also enhance mobility and accommodate larger thighs. Its slanted front pocket reduces phone bounce, and the elastic waistband with internal drawcord allows adjustability. Made from 100% recycled polyester with moisture-wicking comparable to virgin polyester, it undercuts competitors at $80 CAD. The main tradeoff is forgoing the tighter, more technically tailored fit and targeted sweat-wicking of On's Performance Short for a more relaxed, chafe-resistant design.
Verified claims
- Chafe prevention
- Built-in microfibre brief stays in place, separates skin from the outer short, and uses hydrophobic microfiber; the shell's side slits move independently to reduce chafing.
- Sizing
- On lists 6'2" models in Medium, and its regular fit is described as never clingy, so the shorts run large by US performance standards and many runners may size down for the intended relaxed silhouette.
- Stride mobility
- Side slits prevent riding up and accommodate larger thighs without restriction.
- Waist adjustability
- Elastic waistband with internal drawcord resists rolling and allows custom fit.
- Price position
- At $80 CAD (~$60 USD), undercuts Patagonia Strider Pro ($89) and Tracksmith Session ($85).
- Bounce reduction
- Slanted front pocket positions phone diagonally to reduce bounce during runs.
- Stride freedom
- Side slits provide free stride and thigh room without split-short exposure.
- Chafing
- Built-in brief resists chafing by staying in place as the outer short moves.
- Pockets
- The three-pocket layout uses slanted front pockets to hold a phone with reduced bounce, and a concealed rear zip pocket to secure keys and small essentials.
- Lineup comparison
- Forgoes targeted sweat-wicking and racing-informed cut found in On’s Performance Short.
- Fabric
- Shell (100% recycled polyester) resists fading and pilling; hydrophobic liner retains shape through washes.
- Wash care
- Wash cold gentle, dry low; avoid bleach, softener, and iron on reflective logo.
- Moisture-wicking
- Moisture-wicking and breathability match virgin polyester.
- Drawcord
- Internal drawcord fine-tunes fit without overstretching elastic.
- Inner brief
- Built-in microfibre brief stays in place and resists chafing.
- Side slits
- Side slits at the 5-inch hem improve stride mobility and ventilation, and they accommodate larger thighs without the hem pulling or riding up.
- Color durability
- The black recycled-polyester shell resists abrasion and color fading, staying deep and smooth through repeated wash cycles.
- Brief material and support
- The built-in brief is made of lightweight microfibre, not mesh, and is designed to provide support during activities like running; individual fit preferences vary.
- Hot-weather performance
- The ultralight recycled-polyester shell and microfibre brief are synthetic, so they pull sweat off the skin and dry fast, and the 5-inch cut with side slits and single-layer leg panel keeps airflow high; it is built for hot-weather runs and offers no insulation or wind protection.
- Inseam length
- The 5-inch (12.75 cm) inseam is a middle-ground running length that covers the upper inner thigh for chafing protection, stays put on most runners over long runs, and keeps the hem clear for full stride range.
Product record
- Title
- Core 5" Short
- Brand
- On
- Price
- 80 CAD
- Availability
- In stock
Buying Guide
1 comparison · 7 sourcesUses
Lightweight running shorts for distraction-free runs
For running and other fast-paced workouts, these ultra-light shorts pair a 5-inch inseam that balances mobility and coverage with side hem slits for extra movement. The built-in brief is designed to stay in place and resist chafing, while the soft elastic waistband with drawcord lets you adjust the fit. Front drop-in pockets fit a phone, so you can carry essentials with you.[1,2,3]
Product comparison
Compared within this brand.
| Core 5" Short: Choose these for running if you want an ultra-light short with a built-in microfibre brief that On describes as staying in place, feeling soft, and resisting chafing, so no separate liner is needed. The 5-inch inseam, elastic drawcord waist, side hem slits, two drop-in front pockets that fit a phone, and a concealed zippered back pocket cover both mobility and everyday storage. Made from 100% recycled polyester with a stretch lining, they come in Black and Grey in sizes Small through X-Large; note the fabric looks smooth and matte with no visible pattern, so the styling is understated.[1,3,4,5] | Performance 5" Short: Choose this if you want ultra-lightweight running shorts with a built-in microfibre brief, a 5 inch inseam, and a four-way stretch recycled polyamide fabric that is fast drying. They suit runners who want an elastic mesh waist with an adjustable inner drawstring, slant pockets plus a secure back zip pocket, and a reflective logo for visibility. They come in sizes SMALL through X-LARGE, so check sizing if you fall outside that range.[6,7] |
Image Analysis
3 images- 01
Product
Black athletic shorts with a straight cut, smooth woven outer fabric, side pockets, and a small white logo on the lower left front hem; model is wearing the shorts with a tucked white tee which partially covers the waistband.
- SilhouetteStraight-cut above-knee shorts with a relaxed fit and a slightly flared leg opening.
1 region
x 0.32 · y 0.46 · w 0.30 · h 0.26 (high) - Fabric appearanceSmooth, matte woven fabric with no visible texture or pattern in the photographed lighting.
1 region
x 0.32 · y 0.46 · w 0.30 · h 0.20 (medium) - PocketRight side inset pocket visible with model's right hand placed inside.
1 region
x 0.33 · y 0.51 · w 0.14 · h 0.16 (high) - Left front logo“Small white stylized 'on' logo printed near the lower left front hem.”
1 region
x 0.31 · y 0.60 · w 0.05 · h 0.07 (high) - Side hem detailShorts have a short vertical side slit at the outer hem creating a slight overlap between front and back panels.
1 region
x 0.42 · y 0.60 · w 0.08 · h 0.10 (medium) - Waistband visibilityWaistband is largely obscured by the shirt; only the top edge is partially visible beneath the tee.Partial
1 region
x 0.34 · y 0.45 · w 0.18 · h 0.06 (medium)
Other
Studio lifestyle shot showing a standing male model against a plain light grey background; even soft lighting with minimal shadows highlights the clothing contours.
- Model poseMale model standing three-quarter view facing slightly right with left arm relaxed and right hand in pocket.
1 region
x 0.18 · y 0.02 · w 0.64 · h 0.96 (high) - Visible additional clothingModel wears a white short-sleeve crew neck tee and black athletic shoes with white midsoles; these garments are visible but are not analyzed as the primary product.
2 regions
x 0.30 · y 0.04 · w 0.40 · h 0.30 (high); x 0.28 · y 0.72 · w 0.44 · h 0.24 (high) - T-shirt chest logo“Small white or light-colored 'on' logo on the left chest of the tee.”
1 region
x 0.50 · y 0.14 · w 0.05 · h 0.07 (high) - Background and lightingPlain light grey studio background with soft diffuse lighting and minimal cast shadows behind the model.
Colors
matte black· shorts main fabric#141414white· left front logo#DDDDDD- SilhouetteStraight-cut above-knee shorts with a relaxed fit and a slightly flared leg opening.
- 02
Product
Front view of black athletic shorts on a model showing elastic waistband, straight hem with small side slit, and a small white printed logo near the lower left hem.
- WaistbandElastic gathered waistband with evenly spaced horizontal ruching visible across the front top of the shorts.
1 region
x 0.18 · y 0.15 · w 0.64 · h 0.10 (high) - Main fabricSmooth, matte black woven fabric with minimal visible texture and soft drape over the thighs.
- Side seam and slitShort vertical side slit at the hem on each side, with a visible side seam running up from the slit; left side slit is clearly visible.
2 regions
x 0.02 · y 0.68 · w 0.16 · h 0.26 (high); x 0.82 · y 0.66 · w 0.16 · h 0.28 (medium) - Center front seamShallow vertical center seam visible running down the front of the shorts from waistband toward the hem.
1 region
x 0.49 · y 0.24 · w 0.06 · h 0.56 (high) - Logo text“on”
1 region
x 0.06 · y 0.72 · w 0.12 · h 0.12 (high)
Other
Cropped studio shot of a model wearing the shorts against a plain light background; visible hands and upper thighs provide scale. Soft, even lighting with minimal shadows.
- Shot compositionCropped frontal studio shot from waist to mid-thigh showing the shorts on a standing model; torso and arms partially visible.
1 region
x 0.00 · y 0.00 · w 1.00 · h 1.00 (high) - BackgroundSmooth, evenly lit pale gray background with no props or packaging visible.
- Model limbs visibleBoth hands and upper legs of the model are visible and partially cropped at the top and bottom edges of the image.
1 region
x 0.00 · y 0.00 · w 1.00 · h 1.00 (high) - Lighting qualitySoft diffuse lighting with gentle shadows under the waistband and hem, highlighting fabric drape.
Colors
matte black· shorts main fabric#131315white· printed logo- WaistbandElastic gathered waistband with evenly spaced horizontal ruching visible across the front top of the shorts.
- 03
Product
Rear view of a pair of dark athletic shorts with elasticated waistband, rear welt pocket with a small text label on the right, and a small brand logo near the left hem.
- Overall silhouetteRelaxed-fit mid-thigh shorts shown from the rear with a straight hem and a moderate center rear seam.
1 region
x 0.08 · y 0.18 · w 0.84 · h 0.72 (high) - WaistbandElasticated waistband with visible gathered stitching along the top edge; waistband band is the same dark fabric as the short body.
1 region
x 0.12 · y 0.05 · w 0.76 · h 0.16 (high) - Rear pocket flap and labelSmall rear pocket with a horizontal flap on the right back; a narrow rectangular label with white text is stitched onto the flap.
1 region
x 0.68 · y 0.21 · w 0.24 · h 0.10 (high) - Rear pocket text“SWISS ENGINEERING”
1 region
x 0.73 · y 0.23 · w 0.14 · h 0.06 (high) - Left-hem logoSmall white brand mark printed near the lower left hem consisting of two lowercase characters stacked vertically (stylized 'on' logo).
1 region
x 0.03 · y 0.68 · w 0.18 · h 0.20 (high) - Fabric appearanceSmooth, tightly woven synthetic fabric with a matte finish and no visible pattern.
- Center rear seamVertical seam runs down the center of the shorts from the waistband to the crotch area.
1 region
x 0.48 · y 0.22 · w 0.06 · h 0.58 (high)
Other
Studio product shot showing the rear of the shorts worn by a model against a neutral light gray background; visible lower torso, arms, and upper legs provide scale.
- Model and poseMale model shown from mid-back to mid-thigh standing upright; hands relaxed at sides with slight cropping of the left hand.
1 region
x 0.00 · y 0.00 · w 1.00 · h 1.00 (medium) - BackgroundUniform light gray neutral backdrop with soft even lighting and minimal shadowing.
- Shirt visibleWhite textured shirt tucked slightly into the waistband at the back and visible above the shorts.
1 region
x 0.20 · y 0.00 · w 0.60 · h 0.20 (high) - Image crop and framingImage is vertically framed to show the shorts and part of the model's legs; no floor or full body visible.
Colors
black· short body#121215white· left-hem logo#ECECEBwhite· rear pocket label text- Overall silhouetteRelaxed-fit mid-thigh shorts shown from the rear with a straight hem and a moderate center rear seam.
Brand PDP Lookup
- Brand
- On
Men's 5" Core Shorts | On United States
Variants
8 SKUs| SKU | Title | Price | Avail |
|---|---|---|---|
| 4205733 | Core 5" Short - Black - Small | CA$80.00 | Yes |
| 4205734 | Core 5" Short - Black - Medium | CA$80.00 | Yes |
| 4205735 | Core 5" Short - Black - Large | CA$80.00 | Yes |
| 4205736 | Core 5" Short - Black - X-Large | CA$80.00 | Yes |
| 4472983 | Core 5" Short - Grey - Small | CA$80.00 | Yes |
| 4472984 | Core 5" Short - Grey - Medium | CA$80.00 | Yes |
| 4472985 | Core 5" Short - Grey - Large | CA$80.00 | Yes |
| 4472986 | Core 5" Short - Grey - X-Large | CA$80.00 | Yes |