Take a look at the review on Scubapanama in Portobelo on Trip Advisor. I've been diving with them at Portobelo since 2007, and have snorkeled there since 1999.
I haven't dove the Pacific islands, like Taboga. The cost is too much, the water is too cold (for just a skin) and there are no coral -- only rocks. So, I stick to Portobelo and Bocas del Toro. I haven't dove Coiba, yet, but am looking foward to doing so when I can afford to kill two full days just getting from the city to Santa Catalina and back.
So, because it's so close to the city (only 90 minutes), my wife, our friends and I dive Portobelo fairly often. In July, no matter which dive operator in Portobelo you go with, you'll be diving the sheltered sites. There are only a few; Drake Island, Buena Ventura and an old wrecked airplane. The sea will be too rough to go out to the wall until late August. These sheltered sites are fairly shallow -- 25' to a max of 60'. They used to be thick with parrortfish, angels, drums, spotted morays, lobster, crab, octopi and all the small reef fish. The amount of life on and around the reefs was on par with Cayman and any other Caribbean dive spot. In September, I was amazed by how much the population had declined. Whether its from overfishing, silt on the reefs or the invasion of lionfish (saw five on and around one rock), there aren't quite as many fish and critters as there once were.
But, they are still nice dives. The corals are colorful and there are huge gorgonians on Drake Island. (Maybe you can find Drake's long lost lead casket.) Don't expect much viz, though. Depending on the amount of recent rain, it can range from 10 to 50 feet, although I'd say average viz is in the 20 to 30 range.
As for dive operators, I'd go with Scubapanama. They charge much less for rental gear and dives than than Panama Divers. And, you can go with them seven days a week. (It can get a little crowded on the weekends.)
I think Scubapanama also offers better and less expensive accomodations, too. I like their cabanas. They're much closer to Portobelo, which is a good thing, because there are no taxis in the area -- only los diablos rojos, the red devil ex-school busses that are brilliantly painted on the outside, loud as hell with their straight, chromed pipes and cramped (just like a school bus) on the inside. But, for 25 cents a ride, what can you expect?
I'd recommend renting a car and driving. You can pick up a rental at Albrook Airport and avoid all the hassle of driving in the city. (And, it is nightmarishly horrible.) Just turn right on the main road coming out of the airport, keep going along the Panama Canal. When you hit the autopista, head for Colon, pay your toll and when the autopista runs out, turn right at the El Rey supermarket on your right and keep going till you see Scubapanama and Sunset Cabins on your left about 45 minutes later.
The caretaker, Sra. Chong, is also a wonderful cook. She'll cook fish or soup for lunch -- whatever you prefer and same for dinner. She'll also cook a great breakfast to order for you, but you'll pay too much for it. You'll pay $10 for breakfast at Scubapanama. But, if you get in your car and drive one km toward Portobelo you'll pay less than $5 for the same thing at La Torre. La Torre is an excellent restaurant -- the very best on the Caribbean side of Panama (until you get to Bocas). Second best is Los Cañones, which is literally next door to Scubapanama.
One warning about Portobelo -- everything closes up by 7 or 8 pm. So, make sure you eat first before going on a night dive. Or, make arrangements with Sra. Chong to have dinner for you when you get back.
Night dives with Scubapanama are very good. I did two in September and saw morays, octopi, lobster larvae and banded shrimp.
Another reason you'll need a car is to see the historic and cultural sites of Portobelo. You can walk around the ruins of the Spanish forts, go see the Customs House (which once held 1/3rd of the world's wealth in the early 1600s), visit the church of the Black Christ and buy molas from Kuna indians. These women consistently have the best molas I've seen in Panama. It used to be fun to barter with them, but now they're used to gringo tourists saying, "Okay" to their initial price. But, if you're buying more than one, you can usually bargain with them if there aren't a lot of gringos around.
Anyway, that's my dos centavos on Portobelo. Have fun. And, if you do go, take the time to get a water taxi to take you across the bay to the two forts on the hillside. It's worth the adventure in just the view alone.
Buen viaje,
Grant
P.S. The photo illustrates how to get through an intersection in Panama City.
