How would I know what size band I would need when I purchase the Apple Watch Ultra?

LD, the Alpine Loop and Trail Loop (specific to Apple Watch Ultra), come in different sizes. The Ocean band you showed, is the only band which is one size fits all.

Here is a link from Apple, with a sizing tool, which I think the OP is referring to --> https://www.apple.com/shop/Catalog/US/Images/bxxd/size-guide_CA.pdf

To the OP. Take a piece of string and tie it to your wrist where you would typically wear a watch, marking where the two ends meet. Then measure the length and convert to MM. That number will permit you to choose the size band best for your wrist size.

OR, stop by an Apple Store and try the various sizes on.

You do!! BTW., it appears you are wearing the Apple Sport Band, Apple does include both sizes in the box with those.

The issue for band sizing is the loop bands, like Solo, Alpine, Trail, etc. They are essentially one piece and for them, size matters.

Ok that must be Apple being particular. I got mine from a reseller and it came with both sizes. Do you have a measuring tape to measure the circumference of your wrist?

or wrap some string once round your wrist and mark across with a pen. Measure it

Mine is 185cm ie M/L

I would do as I suggested. Cut a piece of string. Mark where it meets on the spot on your wrist where you wear your watch, measure it (if you measure in inches - convert to millimeters) and you'll have your answer.

I did this myself. My wrist, it turns out is 7.25", which is 184 millimeters. So, I bought my Apple Watch Ultra with the Alpine Loop Band. I chose the large Alpine Loop band, which fits wrists from 165–210mm wrists. I could have chosen the medium band, which fits wrists from 145-190mm, but that might have not given me much extra room.

I also purchased the Trail Loop and I bought it in the M/L size as it fits wrists from 145-220mm. The Alpine Loop, comes in three sizes. The Trail Loop, comes in two sizes.

You're very welcome. I hope you enjoy the Ultra as much as I enjoy mine!

The Watch Ultra bands supplied are one-size-fits-all. Only the SE2022 and Series 8 Watches have Sports Bands which come supplied with both sizes in the box anyway.

Thats great, glad we could help.

Sure. But put put the shorter side under the longer side to get a more accurate measurement.

I can already tell you that for the Trail Loop, M/L would be the right band. And I'd get the L Trail loop.

lobsterghost1 wrote:

Sure. But put put the shorter side under the longer side to get a more accurate measurement.

I can already tell you that for the Trail Loop, M/L would be the right band. And I'd get the L Trail loop.

I meant I'd get the L Alpine loop. And M/L Trail Loop, depending on which band you're leaning towards.

And you're most welcome.

No, but maybe you can find the one you want and post a screenshot.