Pelican Marine - IP68 Waterproof Phone Pouch (Regular Size) Floating Waterproof Phone Case - Beach Cruise Ship Travel Essentials - Works with All Phones - Detachable Lanyard - Black/Hi-Vis Yellow

Waterproofness has IP (Ingress Protection). If you want to take pictures underwater look for IP68 which is continuous protection. IP67 is temporary oops I dropped. Floating is another benefit to have. My son snorkeled multiple days for hours at a time wearing his iPhone and taking video underwater using a cheap Pelican case rated at IP68. Not the easiest since it’s plastic. You have to spend a lot more to get glass screen fully submersible cases. https://a.co/d/0gCSc2S3