Free guide
Hydration Vest Size Guide
Vest fit is the single most impactful factor in whether a hydration vest bounces. A vest that fits at rest will bounce badly at mile 40 if it was sized incorrectly. Use this guide to find the right volume and fit for your race distance.
Measuring chest for a vest
Vest brands size by chest circumference, not by torso length like backpacks. Measure at the widest point of your chest (across the nipple line for men, across the fullest part of the bust for women). This is the measurement that determines vest size across Salomon, Ultimate Direction, and Nathan.
- XS: typically 30 to 33 inches chest
- S: typically 33 to 36 inches chest
- M: typically 36 to 39 inches chest
- L: typically 39 to 42 inches chest
- XL: typically 42 to 45 inches chest
Note: Salomon vests run one size smaller than the chart above. If you measure at a Salomon M, order an L. Verify with the brand-specific sizing chart before race day.