Cotton is a crafting component in The Witcher 3: Wild Hunt that is needed to craft thread.
It can be found as both random and guaranteed loot, or purchased from the following merchants:
- All armorers and blacksmiths, except the one at Ardaiso Quarry
- Armors and weapons merchants in Nilfgaardian Army Group 'Center' Camp
- Bram in White Orchard
- Merchant in the boatyard south of Refugees' Camp
- Merchant at Calveit Watchtower
- Merchant at Coast of Wrecks
- Merchant in Putrid Grove
- Merchant in Ursten
- Merchant by the road west of White Eagle Fort
- Scoia'tael merchant in the forest south of Novigrad
- Scoia'tael merchant in the forest east of Oxenfurt
- Quartermaster Eggebracht in Nilfgaardian Army Group 'Center' Camp
- Merchant in Blandare
- Merchant in Fyresdal
- Merchant in Holmstein's Port
- Merchant in Larvik
- Merchant at the sawmill northeast of Rannvaig
- Merchant at the Isolated Hut on Hindarsfjall
- Merchant in Svorlag
- Merchant in Mohrin Village
- Merchant in Stacheier
- Clerk in Villa Vedette
- Merchant outside the The Cockatrice Inn
- Merchant in Dupont & Sons
- Merchant in Flovive
- Merchant in Francollarts
- Merchant in The Clever Clogs Tavern
- Merchant in the Wine Market in San Sebastian
- Pierre in the Tailor's Workshop in Beauclair
- Wandering merchants in Toussaint
- Wine Merchant at Rivecalme Storehouse
Cotton can also be obtained by dismantling thread, and many gauntlets and trousers.