its 6 years since I was in Penang but we used Tour East. We didn't do any boat trips although they did do them. I can't see any of them on their website but you could always email them for details.
They also do trips in Langkawi.

Others may disagree with me (he says rather controvertially!) but Penang is NOT a place for a beach holiday. The main beach Batu Ferringhi has oil tankers 100 metres off shore, and you can see the oil refinery on the mainline.

However, Penang as a destination is great. Georgetown is fab, lots to see and do, so if you can afford it (and it's great value) stay a couple of nights at the Eastern & Oriental, then jump on a firefly flight to Langkawi and have your 5 / 6 nights on a proper beach there.

Just my opinion mind!

I wouldn't disagree Sam. Our hotel was on the beach and we never spent time on it( apart from the beach bar at sunset ) However, it is a really interesting place to visit and we intend to revisit some day.

Also pick your beach on Langkawi with care if snorkelling is a an important part of the holiday to you. The beach round the Westin(previously the Sheraton Perdana) for example is poor with water murky (much like Batu Ferringhi Penang). There are organised tours out for snorkelling on Langkawi easily booked from hotel or local operators.

Not been around for a while. Don't know if you have been.
Been to Penang 6 times. I love it . Would agree its not a beach holiday eg swimmning in the sea but have never seen the oil tankers that close to the beach in Batu Ferringhi. Must agree the sea is awful - mainly mud churned up by the boats using the water but the worst are the jelly fish that hide there, have seen many people badly stung having to have injections for the pain. I love to walk along the beach though. All hotels cater for the tourists and are next to the beach. Like Fiona have spent time at the Sunset Beach.
Looking for things to do- have a Friday Buffet at the Eastern Oriental ( as much as you can eat and drink- wine , beer or soft drinks), go up the fenicular railway on Penang Hill, a walk round the Botanical Gardens, the butterfly farm and batik factory in Telek Bahang, the fruit farm, a walk around Telek Bahang boat trip to the Mukka Island to feed the Monkeys, boat to Langkawi Coral to Snorkell, if your into History there is loads around Georgetown......
As far as eating goes you must try the Hawker Stalls, if staying in Batu Ferringhi go to Long Beach in the evening, for Chinese try the Kampong or Happy Garden, Italian go to Marios and for Indian try The Jewel in The Crown... Looking for cheap lunch go down the pathway beside the Golden Sands and there is a wonderful chinese for lunchtime. If your into nightlife I would suggest you go into Georgetown, batu ferringhi has a couple of bars but I mainly drink around the hotel.
Probably missed loads out- love it and have made many good friends out there. Enjoy.

The beach that the andaman and datai hotels are on is very nice and the water seemed very clear so should be good for swimming etc.