Hi Shea
If you wish to go diving from Penang (without having to fly off somewhere else), the only place to go is Pulau Payar in Langkawi,
<< Langkawi Coral >>
There are a number of tour agencies in Penang which organise trips to Pulau Payar. Most of the major hotels will be able to book you on a trip. Here are the links for 2 agents where you can book on-line if you wish:-
Pulau Payar Marine Park Excursion - Tour Penang
Pulau Payar Marine Park Snorkeling Tour from Penang, Penang Day Trips | Viator.com
The diving is not amazing, but it is more convenient than having to arrange flights/travel to the east coast where the diving is better, but where I think late November is the start of the monsoon season.
Whatever you do, don't forget to check out the very many attractions of Penang. Go to the Kek Lok Si Temple, the Snake Temple, Penang Hill on the funicular railway, the Khoo Kongsi Clan House, Batu Ferringhi beach. For shopping, go to Penang Road, Pasar Chowrastar, the night markets and the bazaars along the Coast Road in Batu Feringghi - make sure you haggle! And don't miss the amazing food that Penang is rightly famous for. You simply must check out the hawker food (found everywhere), the food stalls at the night-markets, and the numerous restaurants serving local food. Amongst the must-trys are char kway teow, popiah, mee rebus, murtabak, chendol and nonya kueh. And if you have time, hire a traditional fishing boat for a day from Batu Ferringhi and ask to go to Monkey Beach.
Have a fabulous time!
Lily