Dominica, not to be confused with the Dominican Republic is in the Lesser Antilles and is two islands south of Antigua in the Winward chain of islands.  Here's the map.
 
Rising 4800 feet from the sea, the 290 square mile island boasts well over 300 fresh clear rivers, the World’s second largest lake of boiling water (the Boiling Lake) and the Eastern Caribbean’s first UNESCO World Heritage Site.

The island is home to the last remaining indigenous people of the Caribbean, the Carib Indians or Kalinago.  Approximately 60% of the island is forested and 30% is protected within the island’s 3 terrestrial National Parks.

Dominica boasts an excellent marine environment and two marine parks that have been established in the island’s waters.  Dominica has over 40 pristine dive sites and is known as the whale watching capital of the Caribbean as it provides resident waters for sperm whales, spotted dolphins and other species. 

The island's precipitous drop-offs create depths just offshore that shelter marine creatures like seahorses, frogfish and flying gurnards which are rarely seen in the other islands. The crests of its submerged peaks are decorated with colorful corals and tropical reef fishes.

• Don't miss the Champagne dive site – a volcanic fissure which pushes a constant stream of bubbles from the seafloor to the surface.  The best time to see this site in all its glory is at night, when the reef explodes with life: huge crabs and lobsters are common sightings.  This site is easily accessible from shore which makes is an ideal snorkeling spot.
• Point Break - loads of large fish at the northern tip of the island where the Caribbean and the Atlantic meet.  Strong currents means this is one for advanced divers
• Dangleben's Pinnacles - a series of 5 pinnacles which create a fantastic maze of dramatic topograpghy that is home to schools of jacks, creole wrasse, yellow tail snappers, turtles, occasional barracuda and an assortment of other creatures.

• The island has three protected marine reserves and, diving there costs an additional US$2 per dive to help protect the environment. 
• A yellow fever vaccination certificate is required from travellers over 1 year of age coming from infected areas.