5) Culebra, Puerto Rico
Culebra, or âLittle Islandâ, is the last island in the Virgin Islands archipelago, and is known for its warm and beautifully clear sea waters, which average between 75F (24C) to 84F (29c) over the year. The surrounding sea is home to a huge and diverse eco-system of birds and other marine animals. If you travel to the largest cay, Culebrita, you will experience the whitest of sand beaches, and water with visibility that âis almost unlimitedâ, according to Puerto Ricoâs tourist website. The coral reefs are regarded as the finest in the Caribbean; so, make sure you book a local tour guide, who will know the exact places for best viewing of ocean and reef life. Culebra still retains a relatively non-touristy feel to it. So, if youâre looking for crystal clear waters in which you can swim alongside spectacular marine life, you can do no better than this little island.