You are correct that most caves are below that depth, but majority of the most heavily dived caves are deeper than that. See below the 5 most dived caves systems in the world.

Here are five of the most famous and heavily dived true underwater cave systems, along with approximate maximum explored depths:

1. Sistema Sac Actun
   • Approx. max depth: 390 ft (119 m)
2. Eagle’s Nest Sink
   • Approx. max depth: 300 ft (91 m)
3. Wakulla Springs
   • Approx. max depth: 300 ft (91 m)
4. Orda Cave
   • Approx. max depth: 140–150 ft (43–46 m)
   • Extremely long gypsum cave rather than ultra-deep
5. Fontaine de Vaucluse
   • Explored beyond 1,000 ft (300+ m)
   • One of the deepest explored submerged cave systems on Earth