Is it ok to snorkel with torn acl?

ACL tear: Check with your orthopedic surgeon. Questions to ask: giving way? Locking? Instability? Full thickness tears? Acute vs chronic? Other joint pathology? Do i need a brace, acl recon, or pt?

Yes, but be careful: There should be no problem with you snorkeling at all. However, i would suggest you be careful getting in and out of the area you are going to snorkel in. There would be a concern for you twisting your knee navigating the entrance and exit, be if rocks, steps or an incline.

Should be fine: No problem. If worried consider a stabilizing brace while snorkeling. Just maker sure brace can be in water without any issues.