Hi, Mike!
Sorry, just saw your message, hope it's not too late.
As a resident, I dive here on a regular basis and I do have some info for you:
January is in the middle of summer here and this means good vis and cold water (for our standards - 18~19 celsius). The best places to dive are indeed some 2 hours distant, both south and north of Rio de Janeiro City. To the south we have Ilha Grande Bay, with calm sea, 360 islands, beautiful landscape and some of our best shipwrecks. The main town in this area is Angra dos Reis, with some good hotels and resorts, boat rentals, dive shops, marinas, shopping malls.
To the north, again 2 hours away from Rio, there are 3 places where diving is possible: Buzios, with only one good diving spot (Anchor Island - Ilha de Ancora) and to get there we spend 1 hour by boat. Although the town itself is a very nice place to visit and is considered a major tourist attraction, the dive tour itself is quite tricky, especially if sea conditions aren't so good (you can look for CASAMAR Dive Center).
There are 2 other places I would rather choose for diving: Cabo Frio, with a very smooth dive operation (look for OVERSEA Dive Center) and some nice diving spots; and last (but not at all least) Arraial do Cabo.
Arraial do Cabo offers world class diving all year round and, together with nice accomodations and good food, a lot of dive centers, atractive prices and, most of all, excellent dive spots! When sea conditions permit, there are really thrilling spots, where I've experienced some of the best dives in my life. Operations in Arraial do Cabo and in Cabo Frio are scheduled for the whole week and the boats are usually completely full on weekends. That's one good reason for going out on week days, if you can, or for booking in advance (I always dive with ARRAIAL SUB Dive Center)!
Just off Rio de Janeiro City, we have the Cagarras Islands, with some good spots and a very interesting shipwreck (a steam ship called the "Buenos Aires" that went down in 1891) which is a challenging dive with depth ranging from 15 to 43 meters (the propeller!). The operations usually take place on weekends and the dive shop is Mar do Rio, located at the Marina da Gloria, a public marina distant only 5 minutes from downtown Rio.
In all those places you can, of course, rent all gear you may need.
For making good diving arrangements without having to go around so much, you can talk to some really cool guys at XDIVERS Scuba School (their site is only in portuguese, but they do speak english, so you can e-mail them). The staff at the dive school can book dive tours for you in all the above mentioned places, plus give you advice on gear, best days to go, accomodations and transportation. You can even arrange for a private guide!
Hope this helps you in any way. If you need any other information concerning your trip or diving in Rio, please contact me. It will be a pleasure to help you out!!
