A total of 13 divers were treated for decompression sickness in Devon after getting into difficulties over the weekend.
Factors such as good weather are blamed for the increase
The Diving Disease Research Centre (DDRC) says the good weather may have contributed to the high number of divers suffering from the "bends".
The bends is caused by divers returning to the surface too quickly.
A combination of factors such as good weather, increased visibility and more visitors have been blamed for the rise.
Phil Bryson, medical director of DDRC, said: "When you get a combination of all those things together, the diving population increases because they haven't been diving for some time and they were fresh and new which is why there was some accidents."
All three of Plymouth's hyperbaric decompression chambers were used.
Linsi Kilminster, from Wales, said she felt nauseous and light-headed and "really, really stressed".
Another diver who was being treated, Chris Manning, said: "After the first dive I was faced with the possibility of being in a wheelchair for the rest of my life but due to the fantastic treatment I've had here, I'm going to make a full recovery."