The XS fit my 3 year-old perfectly. He wears a 4T/5T in most retail brands. He is about 41 inches and 38 lbs.
He was shivering at his swimming lessons (even though they are indoors), he put this on and it was an instant fix! The head hole is rather small, so I have to hold it open to put it over his head for him. I appreciate that it’s resilience as I think the somewhat-fitted neckline helps to keep him warm.
Thermal Swim Shirt YXS. The thermal swim shirt provides warmth to swimmers by trapping body heat with its unique bipoly fabric. Made from a strong. yet lightweight material. the thermal swim shirt conforms to a swimmer's upper body without restricting range of motion. Brand - Finis.