Visit Long Caye, where you can snorkel in the protected lagoons and see the bountiful wildlife, including rare birds, iguanas, and other tropical species. The experience will only be matched by visiting Half Moon Caye, the idyllic island that includes a national park and a bird sanctuary.
You can reach Lighthouse Reef by dive boat or water taxi from Belize City, as well as Caye Caulker and Ambergris Caye. Many snorkeling or diving tours have daily excursions to Lighthouse Reef, highlighting the Great Blue Hole.
If you will be snorkeling or diving, be sure to invest in some high quality water shoes, as walking on the coral reefs can be tricky and potentially painful.
For extended visits, look into resorts on Big Northern Caye and other surrounding areas.