Apple watch strap compatibility
Does apple watch series 10 42mm’s strap fit on series 10 46mm?
No. You can use different straps, of the same size, on different Apple Watch models, of the same size, but you cannot fit a fixed-sized strap on different sized watches.
For example, you can use an Apple 42mm Sport Band or 42mm Sport Solo band on any 42mm Apple Watch, but you can't use any 42mm band on any Apple 46mm watches.