List of reputable tour guides/excursions?

I'm sorry if this has been asked before, but I couldn't find it.

I'll be in Cozumel in May and am looking for a shore excursion, rather than paying the ship's prices. Not certain what I want as yet, but I would like to snorkel, but it is not a must. Right now, I'm just looking for a list of reputable companies/guides. Thanks. :p:p

Tours plaza sells lots of Cozumel tours and is often suggested on this board.

Good snorkeling from the shore at both the Money Bar and Chankanaab. You can do both on your own - taxi from the piers will be about $11 each way. No admission fee for the Money Bar (it is polite to buy food/drinks) and they offer rental gear and snorkel guides if needed.

Chank admission is about $20 per adult, but also offers a small beach separate from the snorkel area, sea lion shows, dolphins, etc.

Cozumel is very safe and easy to do on your own - read reviews on this board and trip advisor, decide what appeals to you, and head out. Most of the popular beach clubs can arrange for a snorkel tour to the reefs (about $30 each for 90 or so minutes) - Paradise Beach, Sanchos, etc.

Thanks John.