What shoe size is Prince Harry?

Size 15 US

It is unlikely that he is a US size 15 shoe, which is huge (especially for someone 6'3). Most American dress shoe makers end at size 16. Kareem Abdul Jabbar was 7'2" and wore a size 16. Kobe Bryant is 6'6" and wears a size 13. The top British shoe makers (including John Lobb and Trickers) generally offer shoe sizes ending with size UK 13, which is roughly a US 13 1/2 or 14, which should give an idea of the largest standard British foot sizes.