Maybe Shark-Ray Alley? The problem is that there's a barrier reef
protecting the Caribbean face of the island. Inside the reef is likely
to be mostly sand and murkier water, though there's probably a fish or
two about.
This site says it best: "You can snorkel off the beach at your hotel
or anywhere on the island, but you don't usually see as much. Some
hotels work hard to keep their piers as appetizing to the fish as
possible. It can be quite pleasant to float around and see what you
can see off shore."
http://www.ambergriscaye.com/pages/town/dive.html
So if "quite pleasant" is your thing, go for it, but it sure doesn't
sound like "world-class" beach snorkeling. On the other hand, maybe
they're just saying that to drum up revenue for the boat operations.
Who knows?
Here's a bit more info, with the following caveat: "The snorkel
transect beyond the relative safety of the docks is best done with at
least two people and a floating diving flag or better yet a boat. Fast
moving skiffs pose a definite menace to the snorkeler."
http://ambergriscaye.com/fieldguide/transect.html
> Also, is there a grocery store in town well enougfh stocked so that
> one can self-cater at a condo?
There are grocery stores in town well-stocked enough for all the ex-
pats and Belizeans that live on the island full or part-time, so I'd
guess yes.