Mens bowling shoes are usually sized in US sizes which are, in most cases, one size larger than their UK counterparts. e.g a US 10 is a UK 9. Both sizes are given in the size selection for each shoe.
Ladies bowling shoes are sized in US sizes which are 2 or 2 /12 sizes larger than UK sizes depending on the manufacturer. e.g. a US 8 1/2 will be a UK 6 in Dexter shoes. Both the UK and US sizes are given in the size selection for each shoe available.