I’d def go YXL, I just got that for my nephew who is quite a tall 10 year old. The shirts aren’t particularly roomy in the body, but very long. My eldest is 8 and needs a YM. Also as advice, if ordering online don’t get any printing done because if you do and size is wrong they won’t take it back, even if it is non personalised stuff like a PL badge on arm |  |