I used to live in Guate. The only good diving occurs on the Sapodilla cays which are technically part of Belize, which should still be part of Guatemala, and which are claimed by Honduras. This caused the cays to be occupied for many years by the British military (kind of like a little piece of Northern Ireland in our own back yard). Needless to say, development suffered on the cays and was limited to Harrier Jump Jets juxtaposed to islanders who had no access to basics like ice and regular electricity. Still it did leave these cays pristine and free of development. The sea life around the Sapodillas was some of the best in the Western Caribbean, definitely worth a trip from Guatemala, Honduras or Belize.