To OP, sorry as I'm only seeing this thread for the first time today.
I stayed and dived with Ocotal in July 2008. I am not sure if they're running boats to Bats Island and Catalina Island during the time you're going. Best to contact the shop directly.
Ocotal requires a dive with them to assess whether they will allow you to dive Bats and Catalina. My first day diving the local site a woman and her son both with horrible buoyancy and a disregard for the UW environment kept landing and kicking up the bottom so they were not allowed on both the Bats and Catalina excursions later in the week. For both Bats and Catalina dives it was a free descent and ascent, no mooring or anchor lines.
Costa Rica is not pretty reef/coral diving, it's volcanic rocks and expect surges and current, viz was about 25 ft with lot of plankton. When I say surges, I mean I saw the diver about 15 ft ahead of me swing like a pendulum, going up about 5 ft and then coming back down 5 ft while swinging in an arc from left to right to left to right, I thought to myself, "Wow, what's he doing?", then I realized I started to swing like a pendulum in the water because I'd entered the surge/current he was in seconds earlier. The surges are not all the time but they are definitely there.
We saw a huge manta ray during our safety stop at Catalina, it swam under my buddies and I, by far the most memorable safety stop to date. Also in Catalina, we saw about a dozen white-tipped sharks of various sizes.
Bats Island was a hot drop into the water and a quick descent to get out of the current otherwise you would get swept in the rocks of Bats Island. We saw seven bull sharks during that dive at Bats Island. We stayed to do a second dive and the viz got worse, only about 5 ft and no bull sharks, what a difference an hour SI will do between dives. :depressed:
We saw lots of different eels/morays and smaller rays on the local dive sites closer to the resort as oppose to Bats and Catalina. Saw lots of different fishes. I'm bad with names of fishes, should really take a Fish ID class.
I know you will have great time in Costa Rica, both diving and topside. Their topside attractions when you're off-gassing are tremendous. Active volcano, rain forest (you can do the suspended bridge tours or swing from the trees), ATV, the wild life and biodiversity of the country is like a living biology class.
Safe travels and safe dives. Report back so we can hear all about your trip.
