I mentioned Panama City because it is an up and comer. It is quickly becoming like San Jose, Costa Rica as the preferred destination for international working girls. I'm told that has to do with changes in Costa Rica's visa laws. I'm not sure though, as I haven't been there yet. But my big-time travel buddies tell me it is like Costa Rica used to be: lots of variety, low prices, girls who aren't quite so "professional".
Colombia is my current favorite location for an "a la carte" vacation. I just think the Colombian women are the most beautiful in the world. It may be a tie between Colombia and Venezuela, but as long as Hugo Chavez is in charge of Venezuela I won't go back there. Pity.
Anyway, Bogota has lots of good opportunities for mongering, but it can be expensive (it is a big city, after all). Cartagena is a major tourist city and of course draws in ladies from all over. There is a beach, although it isn't great. Prices are going to be higher than the rest of the country, but they are used to tourists so you will get along.
I prefer cooler weather and head into the mountains of Colombia, to Medellin. Ladies from here are called "paisas" (country-girls), and they are the finest you'll ever see. Just sitting in a park eating a sandwich watching them walk is a treat. The downtown is full of these hidden "casas" where you can see a parade of ladies and take one back to a room for about $20. Every strip club is a bordello and even the streetwalker strolls are full of women who would turn heads anywhere in the US. Of course they have escort agencies and all kinds of other ways to meet higher-class ladies.
The problem with Medellin is that no one speaks English. Seriously, it is almost unknown. They have no tourist trade to speak of. If you don't speak Spanish you will need to learn some, or hire a guide, or just make do with pointing and grunting. If you are interested in going, check out
http://www.medellinmansion.com/ . It is a hotel owned by an Australian and an American and they cater to guys on sex holidays. There are usually 5-10 working girls hanging around the pool, and Boyd knows every casa in town and will give free guided tours.
But Medellin is in the mountains so it won't work for your scuba vacation. Although direct flights are available from many places. Oh, and Colombia counts as part of the Caribbean for airline miles rewards, at least with American. It is a lot cheaper than the rest of South America (like Brazil).