Anna,
I've been to Panama a few times, and had to opportunity to dive there in September 2005. The diving infrastructure, at least away from Panama City, is in the "development" stage meaning they it's remote (sometimes expensive) and you have to rough it a little bit.
Here's some info and my knowledge on the diving:
Scuba Coiba (
www.scubacoiba.com) Santa Catalina
I dove with them at Isla Coiba, and they were very good. Tough to get to location in Santa Catalina (long bus ride/drive from Santiago). Highlight of dives were being on Coiba, and diving with the sound of Humpback whales singing. Lowlight was I had hoped to see more big marine life (hammerheads, more tuna, barracuda, etc) in large schools.
Buzos de Azuero (
www.dive-n-fishpanama.com) Pedasi
I dove a couple of dives with them at Isla Iguana. Highlight was a dozen Eagle Rays, and they were cheap. Lowlight was poor divemaster.
At both locations you'll be diving out of fishing pangas (no dive boats with platforms and ladders here), and neither are day trips.
Ron Mager (
www.explorationpanama.com) Boca Chica (David Area)
It's not cheap and you'll likely have to arrange for additional divers (or get lucky and hook up with some already planning on diving). We were on Ron's ship (it's a ship - a 50' ex-Coast Guard Search and Rescue) in April 2004 for a sight-seeing and island trip (no diving) and both he and his wife, Yalty, were very nice.
Other diving operations closer to Panama City include:
www.twinoceans.com
www.panamadivers.com - an acquaintance in Panama City dove with them and was impressed, but he had a friend who dove with them and wasn't (depends on the divemaster).
www.scubapanama.com
Also, there are diving operations in Bocas del Toro if you are heading to that area.
