Uniqlo to Athleta leggings size

The short answer

Uniqlo S is Athleta XS or S by the two brands' own charts. 5 of 7 Uniqlo sizes land on a different label at Athleta.

Both brands publish the body waist each size is cut for, so every row matches a waist, not a tag.

Every Uniqlo size read across to Athleta. Letter sizes on the left, Letter on the right.
Uniqlo	Uniqlo builds it for	Athleta, by chart	Same label	Athleta builds it for	Athleta also prints
XXS	waist 22.5 to 24.8 in, hip 32.8 to 35 in	XXS	XXS	waist 24.3 in, hip 34 in	US numeric 00
XS	waist 24 to 26.5 in, hip 34.3 to 36.5 in	XS	XS	waist 25.3 to 26.3 in, hip 35 to 36 in	US numeric 0-2
S	waist 25.5 to 28 in, hip 35.8 to 38.3 in	XS or S	S	waist 25.3 to 26.3 in, hip 35 to 36 in	US numeric 0-2
M	waist 27.3 to 29.5 in, hip 37.5 to 39.8 in	S	M	waist 27.3 to 28.3 in, hip 37 to 38 in	US numeric 4-6
L	waist 29.5 to 32 in, hip 39.8 to 42.3 in	M or L	L	waist 29.3 to 30.3 in, hip 39 to 40 in	US numeric 8-10
XL	waist 32 to 34.3 in, hip 42.3 to 44.5 in	L	XL	waist 31.8 to 33.3 in, hip 41.5 to 43 in	US numeric 12-14
XXL	waist 34.3 to 36.5 in, hip 44.5 to 46.8 in	XL	not published	waist 34.3 in, hip 44.5 in	US numeric 16-18

Tinted rows change label or sit between two sizes. Read from the two charts only; no formula and no averaging.

What wearers say

Charts describe a garment. People who own both brands describe a fit, and their answer ranks above this table once five of them stand behind it. Pick your size in the converter to see whether there are enough yet.

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Sources

Uniqlo size guide, read on 2026-09-18. Uniqlo on TrueToSize
Athleta size guide, read on 2026-09-17. Athleta on TrueToSize

Athleta to Uniqlo