Sorry, no clear tropical waters with reefs. On the Caribbean coast there are some reefs, but more often than not, you cannot dive as there is zero visibility. When you can dive the best we have experienced is about 20' of vis. The best visibility we have seen is at Isla Del Cano. We have been there with several different operations the best being Mad About Diving in Uvita. The negative there is a 1 1/2 hr boat ride each way. Lots of white tips and other large critters and some really nice fish, but no reefs.
The other spot that sticks out is the Catalina Islands, again we have been there with several different operations, the most professional being El Ocotal Resort in Ocotal, but it is a long boat trip from there and they charge a lot for that trip. I recommend Costa Rica Diving in Flamingo, Harald is a lot of fun and they are cheaper than the others in the area. We have heard great things about the Bat Islands, but we can only get there in winter and the seas are too rough that time of year for such a long open water boat trip. The best dive my wife and I ever made was at the Catalina Islands. Devil rays swimming at the surface, dolphins riding the bow wave all the way out and a humpback surfaced right in front of the boat. Once in the water, we have never seen so much life of every description anywhere. The entire dive we were listening to the humpbacks and at our safety stop three 12' mantas combed my wife's hair whlie we were completely surrounded by hundreds of barracuda.
There is a lot to see diving Costa Rica, but if you want Caribbean visibility forget it. The Caribbean is a nutrient poor environment, thus clear water. The eastern Pacific is a nutrient rich environment, thus much poorer visibility, but lots of life.
