Snorkeling and fishing from shore is fun at the public beach of Juan Dolio (the original Playa Juan Dolio).
If you go snorkeling you better keep east or west of the bay and follow the reef. The center of the bay is pretty much just sand and nothing much to see while snorkeling. Be careful and avoid swimming to far out...
You can also fish directly from the beach. You could do so during daylight but usually there are not many fishes to catch this close the the shore - with the exception of the couple times every year big swarms of small sardines come into the bay attracting also bigger hunting fish, then you'll catch at any time of the day and you'll notice a lot of locals also going fishing...
At night the bright illumination from "Popeye's" and "El Bamb?" attracts fishes and even if the catch is not always great, there is a chance you might catch something worthwhile... if not, at least you're most likely to have an enjoyable evening at the beach (which at night is not as crowded as during the day) with a few restaurants and bars around you.
Another good spot not far away is the a little further east of the two parking lots, this is where the local fishermen land their boats, clean the daily catch and throw the rests overboard. At night its a little dark there, but its always a good spot to catch some fish.
