A disaster. . . camera died on the fourth snorkeling trip.
Despite carefully checking the seals before heading underwater for my fourth snorkeling session, the equivalent of two tablespoons of seawater got inside after just an hour. That was enough to kill my Canon EOS R6 and—even after rinsing—cause rust on numerous components outside the camera body.
A watertight seal is maintained by tightening a threaded ring, but there is no mechanism to lock the ring in position. Temperature fluctuations or movements can cause it to loosen at any time, leading to water ingress.
Furthermore, contrary to what was announced, I had to pay an additional €38 in customs duties.