It took a while with Shein to identify what my size was. Eventually after several orders (& having to pay to return items) I worked it out as a Medium. I went to order some swimwear - I ordered a Large as swimwear is often tighter fit. It was tiny and did not even cover me up. I ordered two swimsuits - when I realised this did not fit I didn't even open the other packet. They won't let me return them. Cost of two swimsuits down because THEIR SIZING is totally off. I would probably need a 3XL for one of their suits compared to a medium for trousers, skirts, blouses etc. DO NOT ORDER UNDERWEAR OR SWIMWEAR from them.