Athleta to Uniqlo clothing size

The short answer

Athleta XXS is Uniqlo S by the two brands' own charts. 6 of 6 Athleta sizes land on a different label at Uniqlo.

Both brands publish the body bust each size is cut for, so every row matches a bust, not a letter or a number.

On 5 sizes the charts land two or more sizes from the same label. Brands do not measure the body the same way, so on those rows treat the chart answer and the same label as the two ends of a range.

Every Athleta size read across to Uniqlo Japan sizing. Letter sizes on the left, Letter on the right.
Athleta	Athleta builds it for	Uniqlo Japan sizing, by chart	Same label	Uniqlo builds it for	Uniqlo also prints
XXS	bust 31.5 in, waist 24.3 in, hip 34 in	S	not published	bust 30.3 to 32.7 in, waist 24 to 26.4 in, hip 33.1 to 35.4 in	JP 7
XS	bust 32.5 to 33.5 in, waist 25.3 to 26.3 in, hip 35 to 36 in	M	XS	bust 31.9 to 34.3 in, waist 25.6 to 28 in, hip 34.7 to 37 in	JP 9
S	bust 34.5 to 35.5 in, waist 27.3 to 28.3 in, hip 37 to 38 in	L	S	bust 33.5 to 35.8 in, waist 27.2 to 29.5 in, hip 36.2 to 38.6 in	JP 11
M	bust 36.5 to 37.5 in, waist 29.3 to 30.3 in, hip 39 to 40 in	XL	M	bust 35.8 to 38.2 in, waist 29.5 to 31.9 in, hip 38.6 to 40.9 in	JP 13
L	bust 39 to 40.5 in, waist 31.8 to 33.3 in, hip 41.5 to 43 in	XXL	L	bust 38.2 to 40.6 in, waist 31.9 to 34.3 in, hip 40.9 to 43.3 in	JP 15
XL	bust 42 in, waist 34.3 in, hip 44.5 in	3XL	XL	bust 40.6 to 42.9 in, waist 34.3 to 36.6 in, hip 43.3 to 45.7 in	JP 17
1X	bust 44.3 to 46.3 in, waist 38 to 40 in, hip 47.3 to 49.3 in	not made	not published	not published	not published
2X	bust 48.3 to 50.8 in, waist 42 to 44.5 in, hip 51.3 to 53.8 in	not made	not published	not published	not published
3X	bust 53.3 to 55.8 in, waist 47 to 49.5 in, hip 56.3 to 58.8 in	not made	not published	not published	not published

Tinted rows change label or sit between two sizes. 3 sizes have no counterpart on the Uniqlo chart. Read from the two charts only; no formula and no averaging.

What wearers say

Charts describe a garment, not a fit. We do not collect fit reports for this category yet, so this table is the two brands' own claims and nothing more.

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Sources

Athleta size guide, read on 2026-09-18. Athleta on TrueToSize
Uniqlo Japan sizing size guide, read on 2026-09-25. Uniqlo on TrueToSize

Uniqlo to Athleta