Every genuine pair of Ugg boots should come inside a box with a separate lid that says uggaustralia.com on the side of it. If yours come in a different package, like a plastic bag or paper bag then they're most definitely fake.
Original Ugg soles are flexible. If you are looking at boots with rigid soles, then you’ve got fake ones in your hands. Also check their thickness; authentic Ugg soles are at least ½ inch deep. If the ones in your hands are a bit too thin, don’t waste your money.
Country of manufacture
Ugg boots are generally made in china. If the seller is trying to convince you they are made in Spain or Dubai or any other place apart from china, they're fake.
Try fitting your legs in them and watch to see if they are comfortable enough for your size. Fake ones usually have wider ankles, and are narrower around the heels with shorter fronts that have a steeper angles up the legs, compared to the authentic ones.
Check the fabric labels for overlapping letters in the word UGG as well as the Font size. It should be correctly printed with no sloppy marks. Also, the internal label should say made in china. If it says something else, don’t buy, they're fake.
The boot’s quality is a fine way to tell you exactly what you’re dealing with. Original Ugg boots are incredibly soft inside and smooth outside. If they feel like canvass boots, then they are not real Uggs.
Take note of the boot’s smell. Authentic Ugg boots are made from merino sheepskin, so if you smell anything like chemicals and dyes, as a result of fake sheepskin usage, don’t buy, it isn’t real.
Make sure you analyze every Ugg boot you are looking to buy, properly, using these tips. Be certain not to leave out even the tiniest details, to completely avoid getting deceived when making a purchase.