swim with Apple Watch model no MQL42HN/A ?

Your Apple Watch is water resistant, but not waterproof.* For example, you may wear and use your Apple Watch during exercise (exposure to sweat is OK), in the rain, and while washing your hands.

You can swim with the watch on, but it is not recommended.

Also the water resistant character of any watch is not permanent and decreases with time.

I'd advise you don't go swimming with your watch on, as a precaution.

But the final decision is up to you.

Justin

[Link Edited by Moderator]

Yes you can,read here;

Swim with your Apple Watch – Apple Support