dominica or grenada

Grenada has many more and better beaches, but both are volcanic islands with very limited snorkeling.

I would pick Dominica over Grenada - yes Grenada had alot of beached but the snorkeling in Dominica is unbelievable!
We have never seen such clear water.
I am not sure where i would recomend to stay but we also went inland and swam through a grotto and umped off into a waterfall - it is a very varied island and i wish to return some day!

I'd vote Dominica as well if you're looking for the eco thing. Accommodations are cheaper too. You can find loads of info at http://www.destinationcaribbean.net/index.php?option=com_dcpublishedcountries&task=view_country&id=8&Itemid=35&Itemid2=70
You can fly in via Antigua or St Lucia or Barbados, whichever works best for you.

hi mermaid,

two very good websites to guide you on Dominica are DiscoverDominica.com and Visit-Dominica.com They both have information on accommodation and activities.
If you are staying for 2-3 weeks I would strongly suggest that you stay on different parts of the island because there is quite a bit to see and do and travel time can be long.
In the south-west check out Anchorage, Evergreen, Castle Comfort Lodge, Nature Island Dive to stay at... these are on the sea, excellent for snorkeling and are reasonable in the price-quality mix. You can also do hikes, horseback, four-wheelers, etc from there... Moving to the south-east for a couple of days: Zandoli Inn has no beach and is on rougher waters, but good snorkeling and also other adventure close by.... Back on the west coast (from central to north), check out places in Mero, Salisbury, Coulibistrie or Portsmouth. Sunset Bay Club and Picard Beach Hotel are both ON the beach.... In the North-east, taking you back closer to the airport, look at the properties in Calibishe for another beach + adventure option.

Be sure to go to the waterfalls and bathe in the rivers while you are in Dominica, and feel free to get back at me for more info/advice if you need. I live on Dominica

Another vote for Dominica. Grenada has several more upscale hotels and finer restaurants but the prices for these are 30+5 more. Based on hurricanes and what they damaged in both places over the past few years the snorkeling was better in Dominica in 2006 when we did island hopping on a sail through the Moorings.

I thought I read snorkeling was good in Dominica and diving fantastic....

Seems it's focus is "eco" adventure, sounds like its just what your looking for.