How deep can a pleasure submarine go?

The larger tourist submarines have an operating depth of 100m (330'), smaller ones around 10m (33', or one atmosphere).

It's important to keep in mind that while the deeper depths is modest for a submarine, the reality is that at depths below 100-200', low light visibility and the decrease in aquatic life can make it boring, unless someone is just there for the "ooh's and aah's" of being underwater without Scuba gear.